rOLUMBIA  LIBRARIES  OFFSITE 

'^HEALTH  SCIENCES  STANDARD 


HX64055795 
RD61  C865  Experimental  researc 


RECAP 


I'M'    ' 

[fr" 


I'ilil'llljiifl!'!. 


.1  'I 


ir-'i 


i>  I'  > 


m 


.iiiii,ii;iu,,'fi 


i!i|lf 


f 


I 

mm' 
mMf 


m 


III! 


iiiii:!  i^i'iJi- 
ililliili;-;!' ■  ■  ^'' 


Bought  of 

W.  T.  KEENEE, 

Medical  Booksellek, 

So.  52  Randoleb  St. 

1  CHICAGO.      ' 


■^^Q>V 


G^^S' 


l&tUttntt  BItbrarg 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 

Open  Knowledge  Commons 


http://www.archive.org/details/experimentalresOOcril 


EXPERIMENTAL   RESEARCH 


INTO  THE 


SURGERY  OF  THE  RESPIRATORY 

SYSTEM 


AN   ESSAY   AWAKDED   THE   NICHOLAS  SENN    PKIZE 
BY    THE   AMERICAN   MEDICAL   ASSO- 
CIATION  FOE   1898 


BY 

GEOEGE  W.  CRILE,  A.M.,  M.D.,  Ph.D. 

PROrESSOR    OF    THE    PRINCIPLES    OF   SURGERY    AND    APPLIED    ANATOMY    IN    THE    CLEVELAND    COLLEGE    OF 

PHYSICIANS    AND    SURGEONS;     FORMERLY     PROFESSOR    OF   PHYSIOLOGY    IN     THE   MF.DICAL 

DEPARTMENT  OF   THE   UNIVERSITY   OF   WOOSTER ;   ATTENDING   SURGEON   TO 

THE   ST.   ALEXIS  AND  THE    CLEVELAND   GENERAL   HOSPITALS 


PHILADELPHIA 

J.   B.   LIPPINCOTT  COMPANY 


Copyright,  1899 

BY 

Gkorge  W.  Ckile 


^ 


Printed  by  J.  B.  Lippinoott  Company,  Philadelphia,  U.S.A. 


TABLE   OF   CONTENTS 


PAGE 

I. — Introduction 7 

II, — Methods  of  Kesbarch  and  No'I'ation 8 

III. — On   the  Cause   of   the    Phenomena  attending  the  Inha- 
lation OF  Hot  Air  and  Flame 13 

1.  Preliminary  Remarks      13 

2.  Protocols 14 

3.  Summary  of  Experimental  Evidence      16 

IV". — On  the  Effect  of  Filling  the  Chest  avith  Fluid  ....  18 

1.  Preliminary  Remarks      18 

2.  Protocols 18 

3.  Summary  of  Experimental  Evidence 20 

V. — On  the  Effect  of  Prolonged  Manipulation  of  the  Bra- 
chial  Plexus  and  the  Nerves  supplying  some 

of  the  Muscles  of  Respiration 21 

1.  Preliminary  Remarks 21 

2.  Protocols 21 

3.  Summary 24 

4.  Practical  Application 25 

VI. — On   the  Cause  of  Collapse  or   Death    from  Blows   upon 

THE  Lower  Chest  and  Epigastrium 26 

1.  Preliminary  Remarks 26 

2.  Protocols 26 

3.  Summary  of  Experimental  Evidence 36 

VII. — On  the  Mechanism  of  Drowning      89 

1.  Preliminary  Remarks 39 

2.  Protocols 41 

3.  Summary  of  Experimental  Evidence 58 

VIII. — On  the  Cause  of  Certain  Symptoms  observed  on  entering 

an  Atmosphere  of  Increased  Barometric  Press- 

URK 66 

1.  Preliminary  Remarks 66 

2.  Protocols 66 

3.  Summary  of  Experimental  Evidence 69 


6  TABLE   OF   CONTENTS 

PAGE 

IX. — On  Toreign  Bodies  in  the  Pharynx  and  (Esophagus     .    .  70 

1.  Preliminary  Eemarks 70 

2.  Pfotocols 70 

3.  Summary  of  Experimental  Evidence 77 

4.  Some  Observations 79 

X. — On  Foreign  Bodies  in  the  Trachea  and  Larynx    ,   .    .    .  79 

1.  Preliminary  Eemarks 79 

2.  Protocols 80 

3.  Physiological  Principles  involved 85 

4.  DiflFerential  Diagnosis  between  Lodgement  in  the  Trachea 

and  in  the  Larynx 86 

6.  Preliminary  Preparation  for  Extraction  of  the  Foreign 

Body 87 

6.  On  the  Technique  of  the  Operative  Procedure 88 

XI. — Laryngotomy 98 

L  Preliminary  Eemarks 93 

2.  Principles  involved  in  the  Technique 93 

3.  Treatment  of  Eeflex  Phenomena 94 

XII. — Tracheotomy 94 

L  Preliminary  Eemarks 94 

2.  Experimental  Evidence 94 

3.  Practical  Application 95 

XIII. — Intubation 96 

1.  Preliminary  Eemarks      96 

2.  Protocols 96 

3.  Summary  of  Experimental  Evidence 100 

4.  Clinical  Observations 100 

a.  Eflect  upon  Eespiration 100 

b.  Effect  upon  the  Heart 100 

5.  Collapse  and  Death  due  to  Inhibition 101 

6.  Differential    Diagnosis   between  Obstruction  from   Mem- 

branes pushed  down  and  Collapse  from  Eeflex  Inhi- 
bition      101 

7.  Prevention  of  Collapse  from  Eeflex  Inhibition 103 

8.  Treatment  of  Collapse  from  Eeflex  Inhibition 103 

XIV. — On  the  Cause  of  Certain  Phenomena  attending  Consid- 
erable Traction  on  the  Tongue 105 

1.  Preliminary  Eemarks 105 

2.  Protocols 106 

3.  Summary  of  Experimental  Evidence      Ill 

4.  Practical  Application 113 


EXPERIMENTAL  RESEARCH 


INTO  THE 


SURGERY  OF  THE  RESPIRATORY  SYSTEM 

INTEODUCTION 

From  clinical  observations  it  is  apparent  that  there  are 
a  number  of  phenomena  attending  operations  and  inju- 
ries of  the  thorax  and  the  respiratory  tract  which  are  not 
sufficiently  well  understood  for  ready  application  in  sur- 
gery. Instead  of  taking  up  the  subject  in  a  general  way, 
it  was  thought  best  to  divide  it  into  parts,  and  to  make  a 
research  on  each  subject  separately.  From  the  nature  of 
the  subjects,  some  parts  overlap  others.  It  has  been  only 
within  recent  years  that  opportunities  have  been  general 
for  experimental  work  on  that  part  of  physiology  which 
relates  so  directly  to  surgery.  It  has  been  the  aim  in  this 
work  to  dwell  upon  the  subjects  of  most  practical  impor- 
tance, and  to  elucidate,  as  far  as  possible,  the  practical 
bearings  of  the  several  questions  under  consideration.  It 
is  not  intended  to  be  exhaustive  on -all  the  subjects  taken 
up,  nor  have  all  the  data  accumulated  in  the  experiments 
been  recorded  in  the  protocols,  as  this  would  involve  un- 
necessary detail.  It  was  originally  intended  to  make  the 
research  both  clinical  and  experimental,  but  the  experi- 
mental side  grew  so  large  as  to  make  it  seem  advisable  to 


8       EXPERIMENTAL  RESEARCH  INTO  THE 

keep  the  clinical  in  the  background.  It  was  also  intended 
to  present  a  bibliography  of  the  literature  on  the  various 
subjects,  and  the  greater  part  of  this  has  been  collected, 
but  will  not,  at  the  present  time,  be  added.  The  experi- 
ments have  been  performed  with  great  care,  with  the  sole 
desire  to  arrive  at  the  truth,  without  reference  to  pre- 
vious notions  or  theories.  The  research  has  extended 
over  two  years,  and  was  carried  out  in  the  physiological 
laboratory  of  the  Cleveland  College  of  Physicians  and 
Surgeons.  In  all  the  experiments  dogs  were  used  as  sub- 
jects, and  taken  unselected  as  they  were  supplied  by  the 
laboratory  servant.  I  cannot  sufficiently  acknowledge  my 
indebtedness  to  my  associate,  Dr.  W.  E.  Lower,  who  ren- 
dered most  valuable  assistance  throughout  the  research, 
and  whose  name  deserves  to  appear  on  the  title-page. 

METHODS    OF    KESEAECH    AND    NOTATION 

The  animals  were  all  reduced  to  full  surgical  anaesthe- 
sia before  the  experiments  were  begun,  and  were  killed 
before  recovery  from  the  same.  In  the  greater  num- 
ber of  experiments  ether  was  employed,  and  anaesthesia 
was  produced  by  the  following  method :  A  hood  was 
constructed  so  as  to  accommodate  the  animal's  entire 
head ;  it  was  made  of  strong  cloth,  conical  in  shape, 
and  into  its  apex  was  thrust  a  piece  of  cotton-wool.  Satu- 
rating this  piece  of  cotton-wool  with  the  anaesthetic,  and 
holding  the  hood  closely  over  the  head  of  the  animal, 
reduction  to  surgical  anaesthesia  was  made  with  but  little 
difficulty.  After  the  completion  of  anaesthesia  the  trachea 
was  exposed  and  a  breathing  canula  inserted.  To  the 
free  end  of  this  canula  a  strong  rubber  tubing  was  at- 


SUKUEKY   OF   TIIK   llESJ^niATOIlV    SYSTEM  U 

tached,  and  to  the  end  of  this  tubing  was  fastened  a 
funnel,  which  was  placed  over  a  piece  of  cotton-wool  sat- 
urated with  the  anaesthetic.     By  this  method  anaesthesia 


1.  Instrument  for  recording  respiration. 


2.  Receiving  respiratory  tambour. 


was  easily  maintained  and  no  impediment  offered  to  free 
respiration,  thereby  making  it  possible  to  carry  on  the 


3.  T,  clamp  for  temporarily    4.  S,  glass  canula  for  connecting  the  blood- 
closing  vessels.  vessels  with  the  manometer. 


5.  R,  seeker. 


experiments  with  a  minimum  of  respiratory  error.     The 
respirations  were  recorded  by  means  of  a  tambour  with 


10 


EXPERIMENTAL  RESEARCH  INTO  THE 


rubber  dam  stretched  over  the  ends,  in  the  centre  of 
which  was  fastened  a  disk,  to  which  strings  were  at- 
tached ;   the  free  ends  of  these  strings  were  clamped  to 


6.  Mercurial  manometer  with  graduated  scale. 

the  ends  of  a  piece  of  duck-cloth,  encircling  three-fourths 
of  the  circumference  of  the  animal's  chest.  A  tube  was 
inserted  into  the  centre  of  the  cylindrical  tambour,  into 


SUllGERY   OF   THE   RESPIRATORY   SYSTEM  11 

the  end  of  which  a  rubber  tube  was  attached.  The  free 
end  of  this  tube  was  connected  with  and  set  in  operation 
by  a  simple  respiratory  recording  apparatus  constructed 


7.  Recording  drum. 

of  the  material  and  upon  the  plan  of  an  organ  key.  On 
the  upper  plate  of  the  organ  key  was  attached  a  long 
writing  style,  armed  at  its  free  extremity  with  a  piece  of 
Swedish  steel,  as  thin  as  paper  and  tapering  to  a  deli- 


12 


EXPEKIMENTAL  RESEARCH   INTO   THE 


cate  point,  which  accurately  described  upon  the  smoked 
drum  every  phase  of  the  respiratory  movement.  This 
method  records  only  comparative  respiratory  actions.  The 
blood-pressure  was  recorded  in  the  usual  way,  by  means 
of  mercury  manometers  upon  a  revolving  drum  carry- 
ing smoked  paper,  according  to  the  methods  in  vogue 
in  experimental  physiology.  The  drums  were  revolved 
by  a  mechanism  so  made  as  to  be  capable  of  a  variety  of 


8.  Metronome  arranged  to  make  and  break  the  electric  circuit  at  O  and  P  in  energizing 

the  time-marker. 


movements,  ranging  from  one  revolution  in  thirty  minutes 
to  eighteen  revolutions  per  minute,  so  that  every  phase  of 
any  given  tracing  might  be  duly  recorded.  In  every  ex- 
periment tracings  were  taken,  and  these  have  been  care- 
fully preserved.  Accordingly  there  is  not  a  statement 
made  in  the  following  pages  that  may  not  be  verified  by 
tracings  in  my  possession.    A  sufiicient  number  of  typical 


SURGERY   OF   TUK   RKSlMliATOIlY    SYSTEM  13 

ones  have  been  ])ublislied  to  illuntrute  jijroups  of  their 
kind.  The  method  of  procedure  consisted  in  performing 
the  various  operations  or  imitating  the  various  accidents 
and  conditions  while  graphic  records  were  Ijeing  traced, 
and  on  each  given  subject  a  number  of  records  sufficient 
to  establish  or  corroborate  a  law  were  taken.  The  appa- 
ratus, at  least  a  considerable  part  of  it,  was  especially- 
constructed  to  meet  the  requirements  of  this  particular 
research.  The  number  of  animals  subjected  to  experi- 
ments was  one  hundred  and  two,  and  complete  notes  of 
all  the  experiments  have  been  preserved.  The  notes  were 
made  always  at  the  time  of  the  exjDcriment,  and  every 
detail  was  carefully  recorded,  and  from  these  notes  and 
the  tracings  the  material  for  this  work  was  obtained. 
No  matter  how  faithfully  the  notes  and  the  illustrations 
may  have  been  made,  it  is  impossible  to  impart  the  full 
impression  made  by  the  experiment  uj^on  the  exi^eri- 
menter,  who  receives  the  impressions  at  first  hand. 

EXPERIMENTAL  RESEARCH  INTO  THE  CAUSE  OF  THE  PHE- 
NOMENA ATTENDING  THE  INHALING  OF  HOT  AIR  AND 
FLAME 

Preliminai^y  Remarks. — The  sudden  development  of  the 
phenomena  in  cases  of  collapse  caused  by  the  inhalation 
of  hot  air  and  flame  suggests  an  essential  interference 
with  the  physiological  function  of.  one  or  more  of  the 
nerve  mechanisms  of  the  circulatory  or  respiratory  appa- 
ratus. The  dogs  for  the  experiments  were  placed  under 
chloroform  ansesthesia.  A  large  blow-flame  burner,  used 
in  the  chemical  laboratory  for  glass  blowing,  supplied  a 
flame  that  could  be  adjusted  to  a  very  great  range  of  in- 


14  EXPERIMENTAL  RESEARCH   INTO  THE 

tensity,  and  could  supply  to  the  animal  either  flame  or 
hot  air. 

Protocols. — 1.  On  a  bull-dog  weighing  thirty  pounds, 
with  an  initial  blood-pressure  of  one  hundred  and  sixty- 
two  millimetres  under  chloroform  anaesthesia,  the  fol- 
lowing experiments  were  performed :  The  trachea  was 
dissected  up  and  freed  from  its  attachments,  brought  for- 
ward, severed,  and  the  flame  of  the  blow-pipe  made  to 
play  directly  into  its  lumen.  The  immediate  effect  upon 
the  blood-pressure  was  a  very  sharp  rise,  reaching  two 
hundred  and  six  millimetres.  The  blood-pressure  curve 
was  extremely  irregular,  recording  marked  variations 
with  each  respiratory  movement ;  the  strokes  of  the  ma- 
nometer were  short  and  rapid,  characteristic  of  an  accel- 
erating action  on  the  heart.  The  respirations  at  first  were 
shallow  and  slow,  later  on  became  stronger  and  more 
rapid,  then  gradually  slowing  with  great  amplitude,  finally 
became  smaller  and  ceased.  The  blood-pressure  remained 
high  during  the  first  ten  minutes,  after  which  it  rather 
rapidly  fell  to  the  base  line.  During  the  time  of  inhala- 
tion the  temperature  of  the  animal  rose  four  degrees. 

Autopsy. — Examination  of  the  lungs  did  not  reveal 
any  other  abnormality  than  scattered  points  of  slight 
hemorrhages.  The  disposition  of  the  blood  in  the  circu- 
latory apparatus  did  not  present  any  unusual  features. 
The  intestines  were  pale,  the  kidneys  and  the  liver  nor- 
mal. 

2.  On  a  Newfoundland  dog  weighing  forty  pounds, 
with  initial  blood-pressure  at  one  hundred  and  fifty-six 
millimetres  under  chloroform  anaesthesia,  the  same  ex- 
periments were  repeated.     The  results  were  similar,  with 


SURGEllY   OF   THE   RESPIKATOKY   SYSTEM  15 

the  exception  that  after  breathing  the  flame  for  three 
minutes  the  heart  executed  long  sweeping  strokes  until 
death,  and  the  animal  continuously  breathed  the  flame 
for  twelve  minutes.  The  respirations  at  first  were  shal- 
low, later  they  became  deep,  and  the  inspiratory  phase 
became  particularly  lengthened  and  strong. 

Autopsy. — Intestines  pale,  lungs  slightly  congested ; 
nothing  abnormal  in  the  disposition  of  the  blood  in  the 
vessels. 

3.  On  a  bull-dog  weighing  twenty-eight  pounds,  with 
blood-pressure  at  one  hundred  and  forty  millimetres 
under  chloroform  anaesthesia,  the  same  experiments  were 
performed,  with  results  practically  identical.  In  this 
case  the  heat  was  so  intense  as  to  melt  the  adipose  tissue 
around  the  trachea. 

4.  On  a  mongrel  cur  weighing  nineteen  and  one-half 
pounds,  with  the  blood-pressure  at  one  hundred  and 
eighty  millimetres  under  chloroform  angesthesia,  a  hot- 
air  blast  was  blown  through  the  mouth  into  the  respira- 
tory tract,  which  in  this  case  was  allowed  to  remain 
intact.  Immediately  upon  contact  of  the  hot  air  with 
the  pharynx  and  larynx  there  were  marked  "vagal" 
beats  of  the  heart,  with  a  considerable  fall  in  blood-press- 
ure and  a  sudden  arrest  of  respiration.  The  respiratory 
arrest  was  but  temporary. 

Autopsy. — The  lungs  were  slightly  congested ;  the  heart, 
in  diastole ;  there  were  no  clots ;  the  stomach  was  full  of 
gas ;  the  intestines  pale  and  contracted ;  the  veins  dilated. 

5.  On  a  healthy  poodle  weighing  ten  pounds,  with 
blood-pressure  at  one  hundred  and  twenty  millimetres 
under  chloroform  anaesthesia,  the  following  experiments 


16  EXPERIMENTAL   RESEARCH   INTO   THE 

were  performed :  The  mouth  was  held  wide  open  and  the 
blow-flame  directed  into  the  pharynx  and  the  respiratory 
tract ;  the  immediate  effect  upon  the  blood-pressure  was  a 
temporary  rise,  the  heart-beats  became  slower  and  fuller, 
then  both  vagi  were  severed,  and  again  the  flame  was 
applied  as  before ;  the  heart  now  beat  very  rapidly,  and 
the  blood-pressure  rose  to  two  hundred  and  four  milli- 
metres, continuing  at  this  high  level  for  some  time.  The 
heart  continued  to  beat  rapidly  and  forcibly,  and  the 
curve  of  the  blood-pressure  was  altered  by  each  respira- 
tory act ;  the  rapidity  of  the  heart's  action  increased  until 
it  became  so  rapid,  and  the  length  of  the  strokes  so 
shallow,  that  it  failed  to  register  on  the  drum  ;  the  res- 
pirations at  first  were  much  slowed,  and  for  a  long  time 
were  weak,  but  afterwards  became  strong,  and  remained 
so  to  the  end  of  the  experiment. 

6.  On  a  mongrel  weighing  twenty  pounds,  with  blood- 
pressure  at  one  hundred  and  forty  millimetres  under 
chloroform  anaesthesia,  and  with  a  preliminary  injection 
of  one-one-hundredth  of  a  grain  of  atropine,  the  same  ex- 
periments were  performed  as  in  the  preceding  case.  The 
results  were  the  same  so  far  as  respirations  were  con- 
cerned, but  the  blood-pressure  rose  and  no  "  vagal"  beats 
appeared. 

7.  In  this  experiment  the  preceding  manipulation  was 
repeated,  with  practically  the  same  results. 

8.  Both  vagi  were  cut  and  the  same  experiment  re- 
peated as  described  above ;  the  results  were  practically  the 
same  as  in  Experiments  6  and  7. 

Summary  of  Experimental  Evidence. — The  experimental 
evidence  at  hand  tends  to  show  that  the  direct  effects  of 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  17 

flame  inhaled  into  the  lungs,  with  the  upper  air-passages 
excluded,  are  not  capable  of  causing  sudden  death.  When 
the  flame  is  inhaled  through  the  mouth  and  upper  air- 
passages  as  well,  a  very  marked  reflex  inhibitory  action 
upon  both  the  heart  and  the  respiration  is  produced.  In 
such  a  case,  after  a  control  has  been  taken  (a  control  show- 
ing a  characteristic  inhibitory  action  upon  the  heart  and 
respiration),  when  both  vagi  are  severed,  the  inhibitory 
action  upon  the  heart  is  wholly  prevented,  and,  while  the 
respirations  are  not  so  greatly  altered  in  their  character, 
they  do  not  wholly  escape  reflex  influence.  The  same  may 
be  said  of  similar  experiments  in  which  physiological 
doses  of  atropine  had  been  given.  The  great  irregularity 
of  the  blood-pressure  curve  shows  that  two  factors  are  at 
work  in  its  production, — the  one  an  accelerating,  the  other 
an  inhibiting ;  and  in  the  cases  in  which  the  blast  of  hot 
air  or  flame  was  introduced  through  the  mouth,  both  of 
these  factors  were  brought  simultaneously  into  play,  while 
in  the  experiments  in  which  the  flame  was  forced  into  the 
lungs  through  the  trachea,  but  one  factor — the  acceler- 
ating— was  active.  In  view  of  the  fact  that  hot  air  and 
flame  very  markedly  stimulate  reflex  inhibition  of  the 
heart  and  the  respiration,  it  is  quite  probable  that  the 
sudden  collapse  from  inhaling  hot  air  or  flame  is  due  to 
the  reflex  inhibition  of  the  cardiac  and  respiratory  action, 
in  the  way  just  pointed  out.  Death  may  be  caused  in  a 
few  minutes  by  exhaustion  of  both  the  respiratory  and 
the  circulatory  mechanisms  from  over-stimulation. 


18  EXPERIMENTAL   RESEARCH   INTO   THE 

RESEARCH  INTO  THE  EFFECT  OF    FILLING  THE  CHEST  WITH 

FLUID 

Preliminary  Remarks. — It  occasionally  happens  that 
the  chest  is  rather  suddenly  filled  with  fluid,  and  in  order 
to  determine  the  character  of  the  alterations  thus  produced 
in  the  respiratory  and  cardiac  action,  animals  were  sub- 
jected to  a  rapid  filling  of  the  chest  with  normal  saline 
solution  at  about  the  temperature  of  the  body. 

Protocols. — 1.  On  a  bull-dog  weighing  forty-two  pounds, 
with  initial  blood-pressure  at  one  hundred  and  thirty  mil- 
limetres, the  following  experiments  were  performed :  A 
small  incision  was  made  in  the  integument  over  the  ante- 
rior aspect  of  the  chest,  between  the  fifth  and  sixth  ribs ; 
then,  carefully  guarding  against  the  entrance  of  air,  a 
canula  connected  with  a  siphon  bottle  of  salt  solution  was 
thrust  into  the  pleural  cavity.  The  solution  was  allowed 
to  flow  rapidly  until  two  thousand  five  hundred  cubic 
centimetres  entered,  and  the  following  results  were  noted  : 
As  the  chest  filled,  the  blood-pressure  at  first  slightly 
rose,  the  character  of  the  heart-beats  changed  to  slow, 
full  beats  of  extraordinary  height,  increasing  in  fulness 
for  about  two  minutes,  then  gradually  declining  until 
death  ensued.  The  respirations  were  temporarily  arrested, 
then  executed  slow  and  shallow  excursions  until  the  end, 
which  was  nine  minutes  after  the  beginning  of  the  flow. 

2.  On  a  water-spaniel  weighing  twenty-four  pounds, 
with  blood-pressure  at  one  hundred  and  thirty  millimetres 
under  chloroform  anaesthesia,  the  following  experiment 
was  performed :  The  technique  as  described  in  the  pre- 
ceding case   having  been  carried   out,  a  double  hydro- 


SURGERY   OF   THE    RESPIRATORY   SYSTEM 


19 


thorax  was  induced,  producing  thereby,  as  in  the  former 
experiment,  a  gradual  decline  in  the  blood-pressure,  with 


slow,  full  beats,  showing  very   marked  inhibition.     The 
respirations   were  altered   in   almost   precisely  the   same 


20  EXPERIMENTAL   RESEARCH   INTO  THE 

manner  as  described  in  the  preceding  case.     The  animal 
died  in  twelve  minutes. 

3.  On  a  shepherd-dog  weighing  forty-six  pounds,  with 
initial  blood-pressure  at  one  hundred  and  forty-eight  mil- 
limetres under  chloroform  anaesthesia,  the  preceding  ex- 
periments were  performed  with  almost  identical  results. 

4  and  5.  Two  animals  were  subjected  to  experiment 
under  the  same  conditions  as  in  the  preceding  cases,  with 
practically  the  same  results. 

Summary  of  Experimental  Evidence. — The  experimental 
evidence  at  hand  tends  to  show  that  a  double  hydrothorax, 
rapidly  induced,  is  extremely  fatal.  It  is  impossible  for 
the  lungs  to  become  inflated  when  an  additional  pressure 
to  that  of  the  natural  atmospheric  pressure  is  added  to 
the  resistance  to  be  overcome.  The  phenomena  are  not 
the  same  as  in  pure  asphyxia.  In  pure  asphyxia  the 
blood-pressure  suffers  a  momentary  decline,  after  which 
there  is  an  actual  rise,  oftentimes  a  very  considerable 
rise  above  its  previous  height.  The  character  of  the 
heart's  action  in  asphyxia  experiments  is,  during  the  first 
several  minutes  at  least,  but  little  altered,  thus  making 
a  striking  contrast  to  the  curve  executed  by  the  heart 
in  the  experiment  upon  artificial  hydrothorax.  While 
in  asphyxia  there  is  for  a  time  powerful  respiratory 
effort,  in  these  experiments  a  decreasing  respiratory 
action  is  at  once  inaugurated.  In  any  given  case  of 
sudden  hemorrhage  filling  the  chest,  the  depression  pro- 
duced is  only  in  part  due  to  the  pure  effects  of  abstrac- 
tion of  blood  from  the  general  circulation.  A  consider- 
able factor  in  the  result  is  due  to  the  mechanical  effect  of 
fluid  interfering  with  the  cardiac  and  the  respiratory  action. 


SURGERY   OF   Til  K   RKSIMRATORY   SYSTEM  21 

RESEARCH  INTO  THE  EFFECT  OF  PROLONGED  MANIPU- 
LATION OF  THE  BRACHIAL  PLEXUS  AND  THE  NERVES 
SUPPLYING    SOME    OF    THE    MUSCLES    OF    RESPIRATION 

Prelimjinary  Remarks. — On  several  occasions,  having 
observed  a  dangerous  depth  of  chloroform  narcosis  rap- 
idly induced  in  operations  involving  manipulation  of  the 
brachial  plexus,  a  question  arose  as  to  whether  or  not 
some  cause  for  such  a  result  might  be  found ;  a  research 
into  this  subject  was  therefore  made,  to  determine  whether 
or  not  any  peculiar  effects  upon  the  respiration  or  the 
circulation  attended  operations  in  this  region. 

Protocols.— 1.  On  a  twenty-pound  mongrel,  in  only  fair 
physical  condition,  under  full  ether  anaesthesia,  with  the 
carotid  pressure  and  the  respirations  registering,  after  a 
control  tracing  had  been  secured,  the  following  experi- 
ments were  performed :  The  brachial  plexus  was  exposed 
high  up,  in  close  proximity  to  the  chest-wall,  and  con- 
tinuous manipulating  made,  causing  thereby  an  irregular 
circulatory  curve,  which,  on  the  average,  amounted  to 
a  slight  rise  in  blood-pressure.  At  the  same  time  the 
respirations  were  increased  in  frequency  and  in  depth. 
The  increase  in  frequency  was  such  that  five  respirations 
were  executed  in  the  time  previously  occupied  by  three. 
With  the  increased  amplitude  and  increased  frequency 
there  was  a  very  marked  increase  in  the  total  volume  of 
air  exchanged  in  the  lungs.  This  manipulation  was  con- 
tinued for  ten  minutes,  and  the  respiratory  increase  was 
sustained.  On  cessation  of  the  manipulation  the  respira- 
tory rhythm  was  reduced  in  frequency  and  amplitude  in 
about  the  same  ratio  that  the  manipulation  had  caused 


22  EXPERIMENTAL  RESEARCH   INTO   THE 

the  increase.  On  exposing  the  opposite  plexus  and  repeat- 
ing like  procedures,  equally  striking  results  were  obtained. 
It  was  observed,  however,  that  when  the  principal  traction 
was  made  upon  the  peripheral  nerve-trunks,  the  effect 
upon  the  respiration  was  very  much  less  than  when  the 
traction  was  made  on  the  central  portion  of  the  nerve- 
trunks.  Then,  allowing  the  animal  a  little  time  for  rest, 
an  assistant  repeated  the  manipulation  on  the  one  side, 
while  on  the  opposite  side  similar  manipulation  was  made 
by  myself.  It  was  found  that  the  more  the  central  por- 
tion of  the  trunks  was  stretched  and  manipulated  the  more 
marked  was  the  respiratory  excitation,  and  that  if  during 
this  manipulation  the  anaesthetic  was  inhaled  in  its  usual 
quantity,  an  excessive  anaesthesia  was  induced.  After  a 
considerable  lapse  of  time  the  manipulation  and  traction 
produced  less  marked  respiratory  alterations.  The  nerves 
supplying  the  muscles  of  the  chest  were  then  likewise 
subjected  to  manipulation,  producing  an  increase  in  the 
frequency  and  amplitude  of  the  respirations,  though  not 
so  striking  as  the  preceding. 

2.  Under  chloroform  anaesthesia,  but  in  other  respects 
under  similar  conditions  to  the  preceding  case,  a  fifteen- 
pound  mongrel  was  subjected  to  similar  experiment. 
After  securing  a  control,  the  nerves  were  again  subjected 
to  continued  manipulation,  causing  a  marked  increase  of 
the  respiratory  action  and  very  irregular  blood-pressure 
curve.  Very  soon,  hov^^ever,  the  inhalation  of  the  usual 
amount  of  chloroform  produced  an  over-anaesthesia,  and 
the  blood-pressure  rapidly  sank.  On  cessation  of  the 
manipulations  the  respirations  diminished  very  markedly 
in  frequency  and  amplitude.     The  animal  was  reduced 


SURGERY   OF  THh]    liKSPIRATORY   SYSTEM  23 

almost  to  collapse,  from  which  it  required  considerable 
time,  together  with  artificial  respirations,  to  restore  it. 
After  some  time  had  elapsed  and  restoration  was  com- 
pleted, the  same  procedures  were  repeated  with  like 
results. 

3.  On  an  eighteen-pound  bird-dog  the  following  ex- 
periments w^ere  performed  under  conditions  similar  to  the 
first :  The  skin  was  rapidly  removed  from  the  chest, 
exposing  the  pectoral  muscles.  Manipulation  was  then 
begun  upon  the  muscular  structures  and  the  nerves  of 
extraordinary  muscles  of  respiration.  This  manipulation 
produced  an  increased  respiratory  action,  which  increased 
in  frequency  and  amplitude  as  before.  The  blood- 
pressure,  however,  was  much  less  altered  than  in  the  pre- 
ceding case.  On  cessation  of  this  manipulation,  the  res- 
pirations again  resumed  the  normal  rate.  On  allowing 
the  chloroform  cone  to  remain  in  position,  then  manipu- 
lating the  nerves  and  muscles  on  both  sides  of  the  chest 
simultaneously,  an  over-ansesthesia  was  very  rapidly  in- 
duced. The  over-ansesthesia  was  first  observed  in  the 
marked  depression  of  the  blood-pressure.  After  tbe 
cessation  of  the  manipulations  the  respiration  became 
very  slow  and  shallow,  showing  likewise  the  effect  of  the 
over-ansesthesia. 

4.  A  mongrel,  weighing  nineteen  and  one-half  pounds, 
in  good  condition,  whose  carotid  blood-pressure  was  one 
hundred  and  eight  millimetres,  was  subjected  to  a  simul- 
taneous dissection,  irritation,  and  traction  on  both,  brachial 
plexuses  and  nerve-muscle  apparatuses.  These  meclian- 
ical  stimulations  produced  a  very  marked  increase  in  the 
respiratory  action,  more  than  doubling  that  recorded  in 


24  EXPERIMENTAL   RESEARCH   INTO   THE 

the  control.  Ansesthesia  was  carefully  guarded  during 
the  first  portion  of  the  experiment,  but  in  the  latter  por- 
tion the  anaesthetic  was  allowed  to  remain  with  the  degree 
of  chloroform  saturation  that  was  believed  to  be  safe  in 
sustaining  an  ordinary  anaesthesia.  On  repeating  bi- 
lateral simultaneous  manipulations,  the  respirations  were 
again  very  markedly  increased  in  both  frequency  and  the 
amplitude,  thereby  inducing  very  rapidly  an  over-anses- 
thesia.  This  over-ansesthesia  was  first  observed  in  the 
rapid  decline  of  the  blood-pressure,  and  later  in  the  res- 
piration. When  this  effect  was  noted,  on  cessation  of  the 
manipulation  there  was  a  rather  rapid  failure  of  the  respi- 
ratory action.  Artificial  respiration  was  necessary  to  re- 
store the  animal.  After  this  restoration  the  dog  was  so 
weak  that  it  did  not  readily  respond  to  further  experi- 
ments. 

5.  In  this  experiment  the  foregoing  technique  was  re- 
peated. There  was,  however,  but  little  alteration  in  the 
respiratory  action,  even  though  the  manipulation  was 
quite  as  severe  as  in  the  preceding  case. 

Summary  of  Exjperimental  Evidence. — It  was  found  that 
during  manipulation  of  the  brachial  plexus,  or  of  the 
nerves  supplying  the  muscles  of  respiration,  an  increased 
respiratory  action  was  produced,  resulting  in  over-anaes- 
thesia by  causing  an  excessive  inhalation.  This  was 
specially  true  in  experiments  in  which  chloroform  was 
administered.  On  the  cessation  of  the  manipulation  the 
normal  respiratory  action  was  resumed.  It  was  found, 
however,  that  by  continuing  the  manipulation  of  these 
structures  there  was  a  greater  tendency  towards  respi- 
ratory failure  later  on  in  the  experiment.     It  is  true  that 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  25 

mechanical  stimulation  of  any  nerve  will  produce  in- 
creased respiratory  action.  It  would  seem  that  the  ma- 
nipulation of  the  respiratory  nerve-muscle  apparatus  or 
nerve  trunks  may  affect  the  respiratory  action  to  an  ex- 
tent sufficient  to  constitute  a  danger  of  over-anaesthesia, 
provided  the  inhaled  air  is  saturated  with  the  anaesthetic 
to  the  same  degree  as  in  the  control.  In  such  experi- 
ments an  earlier  break-down  of  the  respiratory  mechan- 
ism occurs. 

On  cessation  of  a  severe  manipulation,  respiratory  de- 
pression or  failure  is  very  likely  to  occur,  because  then, 
the  mechanical  stimulation  having  been  withdrawn,  the 
mechanism  is  thrown  upon  its  own  resources,  which  have 
been  much  impaired  by  the  jDrevious  stimulation. 

Practical  Application. — The  depression  referred  to  in 
the  preliminary  remarks  would  probably  appear  only  in 
cases  involving  rather  direct  manipulation  of  these  nerve- 
structures,  and  more  readily  in  chloroform  anaesthesia  on 
account  of  the  relatively  greater  potency  of  this  anaesthetic. 

But  the  point  of  greatest  practical  importance  is  the 
proper  interpretation  on  the  part  of  the  anaesthetizer  of 
the  cause  of  the  increased  action.  Such  increased  action 
would  ordinarily  be  interpreted  as  a  symptom  of  under- 
anaesthesia,  and  at  once  suggest  giving  more  anaesthetic. 
Under  these  circumstances  the  anaesthetic  effect  would  be 
more  marked  upon  the  circulation  than  upon  the  respira- 
tion until  the  patient  sinks  into  a  collapse  more  or  less 
profound.  The  respiratory  depression  appears  later  be- 
cause of  the  mechanical  stimulation  which  will  maintain 
respiratory  activity  until  the  centres  are  exhausted. 


26      EXPERIMENTAL  RESEARCH  INTO  THE 

RESEARCH  INTO  THE  CAUSE  OF  COLLAPSE  OR  DEATH 
FROM  BLOWS  UPON  THE  LOWER  CHEST  AND  THE  EPI- 
GASTRIUM 

Preliminary  Remarks. — This  research  was  suggested  by 
the  number  of  cases  of  collapse  and  even  death  following 
blows  delivered  upon  the  chest,  more  especially  over  the 
lower  portion  of  the  left  anterior  chest-wall  and  upon  the 
so-called  "  pit  of  the  stomach." 

In  the  history  of  these  cases  it  is  usually  stated  that 
such  results  instantly  followed  the  application  of  the  vio- 
lence, and  that  if  death  did  not  immediately  follow,  re- 
covery took  place. 

The  so-called  "short  rib"  and  "solar  plexus"  blows, 
well  known  in  pugilistic  encounters,  are  examples. 

The  following  have  been  the  principal  theories  ad- 
vanced as  to  the  manner  of  the  production  of  the  effect : 
That  the  blow  produced  mechanical  stimulation  of  the 
solar  plexus,  thereby  causing  cardiac  arrest;  that  the 
diaphragm  was  injured,  causing  respiratory  arrest  or 
spasm  of  this  organ ;  that  the  heart  itself  was  injured  ; 
and  that  the  heart-failure  was  due  to  mechanical  stimu- 
lation of  the  vagus. 

Protocols. — 1.  A  shepherd-dog,  weighing  twenty  pounds, 
in  good  physical  condition,  was  placed  under  full  ether 
anaesthesia,  and  arrangements  made  for  securing  graphic 
records  of  the  respiration  and  of  the  carotid  blood-pressure. 
After  control  tracings  had  been  secured,  a  severe  blow 
was  delivered  with  a  rather  heavy  handle  of  a  hammer 
directly  upon  the  chest  over  the  point  of  appearance  of 
the  apex-beat.     The  heart  was  instantly  arrested  and  the 


SUKGEllY   OF  THE   RESPIllATORY   SYSTEM  27 

blood-pressure  fell  to  the  abscissa  line,  from  which  it  did 
not  again  rise.  The  heart  did  not  make  a  single  observa- 
ble effort  towards  resuming  its  function.  The  respirations 
were  temporarily  completely  arrested,  then  there  were 
several  rather  feeble  respiratory  efforts,  becoming  more 
shallow  and  appearing  at  longer  intervals  until  they  en- 
tirely failed.  The  animal  instantly  died  from  the  effect 
of  the  single  blow  delivered  in  the  manner  above  de- 
scribed. 

Autopsy. — The  heart  was  found  in  diastole,  all  the 
chambers  containing  more  or  less  blood.  There  was  no 
observable  lesion  of  the  pericardium  or  of  the  heart- 
muscle. 

2.  On  a  water-spaniel,  weighing  eighteen  pounds,  in  fair 
condition,  under  surgical  ether  anaesthesia,  with  arrange- 
ments for  graphic  records,  as  in  the  preceding,  a  direct 
blow  was  delivered  upon  the  chest  over  the  heart.  The 
blood-pressure  underwent  an  immediate  staggering  fall ; 
the  heart-strokes  were  slow,  full,  but  irregular ;  the  blood- 
pressure  curve  was  correspondingly  irregular,  but  at  the 
end  of  sixty-five  seconds  it  had  gained  the  same  height  it 
occupied  before  the  blow  was  delivered.  The  respirations 
were  momentarily  arrested,  and  they  became  irregular, 
but  their  amplitude  was  almost  doubled.  This  increased 
amplitude  and  increased  pause  with  irregularity  continued 
during  the  space  of  time  in  which  eight  respiratory  exciir- 
sions  would  have  been  made,  on  the  basis  of  the  same  rate 
at  which  the  respiratory  actions  were  performed  at  the 
time  of  delivering  the  blow.  The  same  experiment  was 
subsequently  twice  repeated,  and  in  each  case  with  prac- 
tically the  same  results.     The  left  vagus  was  then  sev- 


28  EXPERIMENTAL   RESEARCH   INTO   THE 

ered,  after  which  there  was  an  increase  in  the  respiratory 
depth  and  no  effect  observed  upon  the  circulation.  On 
severing  the  right  vagus,  respirations  ceased  for  a  time 
equal  to  that  required  for  three  normal  respiratory  ex- 
cursions, then  the  respirations  were  gradually  increased 
in  their  amplitude,  their  rapidity  remaining  about  the 


l4\JrA  U»w    (U^U^ 


mBsmi 

AH'lIiiWiHlilfia 

mmmmmmiiii 

,.vL.iiii*i*W'tomitfr*''"''iiti 

^lyiWI'l'"  1  inn"n'li''i'i|            ff'P 

'"\/^l 

^to-iP  aJJ«+i«.  cImaV 

10.  Blow  upon  the  Chest  over  the  Heart. — Note  the  abrupt  fall  in  the  blood-pressure 
(second  tracing),  and  the  irregular  heart-action  afterwards. 

same.  The  heart  was  arrested  for  three  seconds ;  then, 
after  a  few  slow  beats,  it  increased  very  considerably  in 
the  rapidity,  and  the  excursions  of  the  manometer  were 
diminished  in  length.  On  repeating  the  direct  blow  upon 
the  chest  quite  as  forcibly  as  before,  an  interference  with 
the  respiration  and  the  circulation,  similar  to  that  noted 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  29 

previous  to  section  of  the  vagi,  was  observed.  The  blows 
were  twice  more  delivered,  each  time  producing  like  re- 
spiratory and  circulatory  phenomena. 

3.  A  water-spaniel,  weighing  twenty-five  pounds,  under 
ether  anaesthesia,  with  arrangements  for  records  as  in  the 
preceding  case,  was  subjected  to  the  following  experi- 
ments : 

(a)  After  securing  control  tracings,  a  blow  from  a 
light  hammer  was  directed  upon  the  chest  over  the  heart, 
causing  thereby  a  sudden  drop  in  the  blood-pressure, 
with  temporary  cessation  of  cardiac  action,  followed  by 
sweeping  beats  at  about  twice  the  interval  observed  before 
the  experiment.  The  blood-pressure  curve  during  this 
time  was  irregular,  and  in  thirty-six  seconds  had  risen  to 
the  level  it  occupied  before  the  experiment.  The  res- 
pirations were  irregular  during  eight  seconds. 

(b)  The  same  experiment  was  repeated  with  like  results. 

(c)  Both  vagi  were  severed,  producing  variations 
during  the  performance  of  this  operation  similar  to  those 
described  in  the  first  experiment,  so  that  after  both  had 
been  severed  the  heart  beat  more  rapidly,  the  blood- 
pressure  slightly  rose,  the  cardiac  strokes  were  shorter, 
the  respirations  deeper  and  a  little  slower. 

{d)  A  blow  was  now  delivered  upon  the  chest  over 
the  heart,  as  nearly  like  preceding  as  possible.  There 
was  practically  no  effect  on  the  respirations,  but  the  blood- 
pressure  failed  suddenly  as  before,  the  character  of  the 
beats  was  the  same,  and  the  blood-pressure  was  regained 
in  about  the  same  time. 

(e)  The  same  experiment  was  repeated  with  practically 
the  same  results. 


30  EXPERIMENTAL   RESEARCH   INTO   THE 

4.  On  a  shepherd-dog  weighing  twenty  pounds,  under 
ether  anaesthesia,  with  arrangements  for  records  as  in  the 
preceding,  the  following  experiments  were  performed : 

(a)  A  blow  upon  the  chest  directly  over  the  heart  pro- 
duced a  marked  fall  in  the  blood-pressure,  with  "  vagal" 
beats  continuing  for  some  time ;  then  the  "  vagal"  beats 
suddenly  gave  way  to  small,  shallow,  and  extremely  rapid 
beats.  The  respirations  were  temporarily  irregular,  but 
not  greatly  disturbed. 

{b)  Both  vagi  severed,  producing  the  phenomena  de- 
scribed in  Protocol  1,  and  when  both  had  been  severed 
the  blood-pressure  rose,  while  the  respirations  became 
deeper  and  slower. 

(c)  A  blow  delivered  upon  the  chest  over  the  heart,  as 
in  (a),  did  not  produce  any  alterations  in  respiration. 
There  was  a  sudden  fall  in  the  blood-pressure;  during 
this  time  the  heart  executed  three  slow  "  vagal"  beats, 
then  quickly  regained  the  normal  level  of  pressure. 

(d)  Injected  one-one-hundredth  of  a  grain  of  atropine 
into  the  jugular  vein ;  after  the  lapse  of  one  minute, 
stimulated  the  peripheral  end  of  the  severed  vagus  by 
applying  the  electrode  of  a  Du  Bois-Reymond  coil,  whose 
secondary  coil  was  overlapping  the  primary  by  one-half. 
This  electrical  stimulation,  though  more  than  sufficient 
to  cause  inhibition  of  the  heart,  did  not  affect  a  single 
beat.  This  was  done  as  a  control  to  test  the  full  physi- 
ological action  upon  the  terminals  of  the  vagus  in  the 
heart,  so  that  if,  in  a  subsequent  experiment,  the  heart 
again  was  affected,  it  could  not  be  due  to  a  mechanical 
stimulation  of  the  vagus,  either  its  branches  or  its  ter- 
minals. 


SURGERY   OF  THE    IIKSIMRATORY   SYSTEM 


81 


(e)  A  blow  as  nearly  similar  as  possible  to  those  pre- 
viously given,  was  then  directed  upon  the  chest  over  the 
heart,  producing  a  sudden  fall  in  the  blood-pressure  with 
four  beats  of  like  character  to  those  described  under  (c), 


)h4,    /4T'V^^r^, 


mMms^jm^ 


V  .*»\ 


m'^' 


a.>..vwa  «.y;.  "t-Jia;' 


11.  The  upper  tracing  represents  the  respiratory  action,  the  next  tlie  blood-pressure.  At 
the  lower  margin  are  the  signals  and  time-marker  (seconds).  Note  the  momentary  rise,  fol- 
lowed by  the  collapse  in  the  circulation  after  the  lungs  were  subjected  to  pressure  of  thirty 
inches  of  water. 

the  blood-pressure  regaining  its  previous  level  after  exe- 
cuting a  curve  in  all  respects  similar  to  that  in  [a).  The 
respirations  were  not  affected. 

(/)  The  same  experiment  repeated  with  like  results. 

5.  On  a  healthy  mongrel  dog  weighing  eighteen 
pounds,  under  conditions  as  nearly  like  the  preceding  as 
possible,  like  experiments  were  performed  with  results 
essentially   the  same, — that  is   to   say,  after  control  ex- 


32  EXPERIMENTAL   RESEARCH   INTO   THE 

periments  the  vagi  were  cut,  and  after  testing  the  effects 
with  severed  vagi,  atropine  was  given  as  in  the  preceding ; 
then  the  same  experiment  was  repeated,  obtaining  prac- 
tically the  same  results. 

6.  On  a  mongrel  dog  weighing  fifteen  pounds,  under 
conditions  similar  to  the  preceding,  the  following  experi- 
ments were  performed : 

(a)  A  control  blow  over  the  right  side  of  the  chest  was 
delivered,  causing  thereby  temporary  irregularity  in  the 
respiratory  action  and  a  marked  fall  in  blood-pressure, 
produced  by  a  single  intermission. 

(b)  Similar  effects  were  produced  by  delivering  blows 
with  considerable  force  over  various  portions  of  the  chest. 
However,  the  nearer  the  heart  area  the  more  marked  was 
the  effect. 

(c)  With  the  vagi  cut  similar  blows  produced  like  re- 
sults upon  the  circulation,  but  no  effect  on  respiration. 

7.  On  a  shepherd-dog  weighing  twenty-five  pounds, 
under  conditions  similar  to  the  preceding,  the  following 
experiments  were  performed : 

(a)  A  blow  delivered  with  great  force  over  the  "  pit  of 
the  stomach"  produced  a  sudden  drop  in  the  blood-press- 
ure, continuing  during  the  time  of  a  single  beat.  The 
respirations  were  but  momentarily  altered. 

(b)  A  similar  blow  upon  the  abdomen  over  the  um- 
bilicus produced  no  effect. 

(c)  A  blow  was  delivered  over  the  kidneys  and  the 
lower  abdomen,  but  produced  no  effects. 

(d)  As  a  control,  a  blow  was  again  delivered  upon  the 
chest  over  the  heart,  producing  a  more  gradual  though 
marked  fall,  which  was  recovered  in  ten  seconds. 


SURGERY   OF   TITE   RESPIRATORY   SYSTEM  33 

8.  On  a  thirteen-pound  mongrel  dog,  under  conditions 
like  the  preceding,  the  following  experiments  were  per- 
formed : 

(a)  As  a  control,  a  blow  was  delivered  over  the  heart 
with  the  usual  results. 

(b)  A  severe  blow  was  delivered  over  the  "  pit  of  the 
stomach,"  with  results  similar  though  less  pronounced. 

{g)  The  stomach  was  freely  exposed  by  a  median  in- 
cision and  a  considerable  quantity  of  air  forced  into  it 
through  the  oesophagus,  then  the  oesophagus  was  se- 
curely tied.  The  pylorus  was  also  securely  tied.  A 
blow  was  then  delivered  directly  upon  the  stomach, 
with  its  force  directed  a  little  upward,  producing  a  fall 
in  blood-pressure  similar  to,  though  less  marked  than 
in  (a). 

id)  The  stomach  blow  was  repeated  after  section  of  the 
vagi  with  similar  results.  Also  after  the  injection  of  one- 
one-hundredth  of  a  grain  of  atropine  into  the  jugular  vein, 
with  similar  results. 

9.  On  a  yellow  mongrel  dog  weighing  fifteen  pounds, 
under  conditions  similar  to  the  preceding,  the  following 
experiments  were  performed : 

(a)  Placing  the  dog  upon  his  right  side,  a  severe  blow 
was  delivered  upon  the  chest  in  the  left  axillary  line,  pro- 
ducing results  similar  to  the  blow  directly  over  the  heart, 
though  less  marked. 

{b)  Placing  the  dog  upon  the  left  side,  a  similar  experi- 
ment was  performed  upon  the  right,  with  similar  results, 
though  less  marked  in  degree.  A  blow  delivered  directly 
over  the  heart  caused  but  a  momentary  drop  in  the  blood- 
pressure,  but  this  drop  was  deeper  than  in  the  case  in 


34  EXPERIMENTAL  RESEARCH   INTO   THE 

which  the  blow  was  delivered  upon  the  side.  It  was 
found  on  repeating  the  blows,  even  with  increasing  se- 
verity, that  the  effect  upon  the  blood-pressure  was  in 
each  subsequent  experiment  lessened.  At  the  autopsy 
it  was  found  that  the  heart  itself  was  partially  ruptured 
and  the  pericardium  contained  a  considerable  amount  of 
blood ;  three  ribs  had  also  been  broken  by  the  violence 
of  the  blows. 

10.  On  a  sixteen-pound  yellow  mongrel,  after  making 
a  free  exposure  of  the  diaphragm  by  an  abdominal  in- 
cision and  removing  the  stomach  from  its  relation  to  this 
organ,  direct  pressure  was  exerted  upward  against  the 
apex  of  the  heart,  producing  thereby  a  very  marked 
arythmia  and  a  very  irregular  blood-pressure  curve, 
which,  on  the  average,  amounted  to  a  fall.  These  phe- 
nomena continued  as  long  as  the  mechanical  interfer- 
ence through  the  diaphragm  continued.  It  was  found 
that  even  comparatively  slight  pressure  upward  upon  the 
diajDhragm  against  the  apex  of  the  heart  produced  great 
disturbance  in  the  cardiac  action.  This  disturbance  was 
characterized  by  a  very  great  irregularity  in  the  force  of 
the  beat,  in  the  length  of  the  strokes,  and  in  their  rhythm, 
producing  thereby  a  very  irregular  blood-pressure  curve. 
Placing  the  end  of  a  hammer  over  the  diaphragm  at  the 
point  where  the  apex  impulse  could  be  made  out,  then 
delivering  a  blow  upon  the  distal  end  of  the  hammer, 
produced  a  staggering  fall  in  the  blood-pressure,  with 
very  marked  irregularity  of  the  heart-beats.  Repeating 
this  same  manoeuvre  on  the  right  side  of  the  diaphragm, 
away  from  contact  with  the  heart,  no  cardiac  effect  was 
noted.     Likewise  repeating  the  same  on  the  extreme  left 


SURGERY   OF   TEE   RESPIRATORY   SYSTEM  ?>6 

border  of  the  diaphragm,  directing  its  force  downward 
towards  the  ribs  and  therefore  away  from  the  heart,  no 
cardiac  disturbance  was  noted. 

11.  A  yonng  water-spaniel,  weighing  sixteen  pounds, 
was  subjected  to  experiments  similar  to  the  preceding, 
producing  results  in  all  respects  similar.  In  addition  to 
these,  the  closed  hand  was  placed  against  the  abdominal 
side  of  the  diaphragm,  gradually  pushing  this  organ  up- 
ward ;  at  first  no  effects  were  produced,  but  when  this 
pressure  was  increased  and  the  area  of  cardiac  activity 
was  further  encroached  upon,  irregularities  in  action  simi- 
lar to  the  preceding  were  observed.  The  chest-wall  was 
then  cut  away  over  the  heart  and  a  smart  blow  was  deliv- 
ered directly  upon  that  organ,  j^roducing  a  fall  in  blood- 
pressure  and  an  alteration  in  the  cardiac  action,  similar 
to  those  heretofore  described. 

12.  A  savage  bull-dog,  weighing  forty  pounds,  was  sub- 
jected to  the  following  experiments :  Artificial  respira- 
tions were  maintained,  and  the  thorax  over  the  heart  was 
cut  away  so  as  to  expose  it.  Blows  were  then  delivered 
upon  the  heart  itself,  producing  effects  entirely  similar 
to  those  noted  in  the  preceding  experiments.  The  peri- 
cardium was  then  incised  and  the  heart-muscle  itself  sub- 
jected to  similar  treatment,  producing  similar  results. 
Any  interference  with  the  heart,  as  an  organ,  produced 
a  staggering  fall  in  the  blood-pressure,  and,  on  the  with- 
drawal of  the  mechanical  stimulation  or  interference,  the 
blood-pressure  curve  would  rapidly  rise  again.  This 
very  soon  exhausted  the  animal. 

13.  A  shepherd  dog  in  good  condition,  weighing  four- 
teen and  one-half  pounds,  was  subjected  to  the  same  pro- 


36  EXPERIMENTAL  RESEARCH  INTO  THE 

cedure  as  in  the  preceding  case,  with,  in  the  main,  the 
same  results. 

14.  A  mongrel-dog,  weighing  fifteen  pounds,  in  good 
condition.  After  a  control  had  been  taken,  an  incision 
was  made  through  the  abdomen,  and  the  viscera  were 
withdrawn  so  as  to  expose  the  solar  plexus.  A  blow  was 
delivered  upon  the  plexus,  the  force  of  which  was  so  direct 
as  to  interfere  as  little  as  possible  with  the  large  blood- 
vessels. No  effect  upon  the  heart  was  noted.  The  solar 
plexus  was  then  grasped  between  the  fingers  and  manipu- 
lated as  rudely  as  possible,  without  producing  any  direct 
effect  upon  the  heart.  During  this  manipulation,  how- 
ever, there  was  a  gradual  decline  in  the  blood-pressure 
pari  passu  with  the  dilatation  of  blood-vessels  in  the 
splanchnic  area.  Finally,  as  a  control,  a  blow  was  de- 
livered over  the  heart,  producing  the  changes  in  cardiac 
action  and  blood-pressure  described  in  previous  experi- 
ments. 

15.  On  a  sixteen-pound  bird-dog  the  same  experiments 
were  performed  as  in  the  preceding  case,  with  practically 
the  same  results.  No  amount  of  manipulation  or  mechan- 
ical injury  of  the  solar  plexus  or  the  splanchnic  trunks 
produced  any  sudden  change  in  the  blood-pressure  or  in 
the  cardiac  action.  It  did  produce  a  gradual  decline  in 
the  blood-pressure,  as  in  the  preceding  experiment.  The 
control  blow  delivered  directly  upon  the  heart  caused  the 
usual  results,  though  to  a  rather  light  degree. 

Summary  of  Experimental  Evidence. — No  amount  of 
injury  inflicted  upon  the  solar  plexus,  either  directly  or 
indirectly,  was  capable  of  causing  any  inhibitory  action 
upon  the  heart,  and  in  no  way  did  such  injury  contribute 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  37 

to  the  immediate  death  or  collapse  referred  to,  but  the 
effect  this  manipulation  did  have  was  to  produce  a  vaso- 
dilatation of  the  "splanchnic  area,"  thereby  causing  a 
gradual  decline  in  the  blood-pressure. 

In  experiments  in  which  the  abdomen  was  opened  and 
the  diaphragm  protected  from  indirect  violence,  blows 
upon  the  stomach  alone  produced  but  little  effect  upon  the 
blood-pressure  or  the  respiration. 

In  other  experiments  in  which  the  diaphragm  was  not 
protected  from  indirect  violence  transmitted  through  the 
stomach  or  other  viscera,  blows  delivered  upon  the  pit  of 
the  stomach,  especially  when  the  stomach  was  distended, 
produced  sometimes  a  momentary  staggering  fall  in  the 
blood-pressure.  In  some  cases  the  pressure  remained  at 
a  lower  level  and  described  a  very  irregular  curve,  then 
finally  regained  the  height  of  the  control. 

Pressure  suddenly  applied,  or  blows  directly  upon  the 
diaphragm  within  the  cardiac  zone,  produced  usually  a 
very  marked  drop  in  the  blood-pressure.  In  some  cases 
but  a  single  intermission  of  the  heart-beat  was  produced, 
in  others  the  blood-pressure  suffered  a  great  fall,  and 
slowly  and  with  great  irregularity  of  action  regained  the 
lost  pressure.  Even  carefully  pressing  with  the  hand 
upward  against  the  diaphragm  so  as  to  produce  by  such 
pressure  an  interference  with  the  freest  movement  of  the 
apex  caused  a  very  great  cardiac  irregularity  and  an 
irregular  blood-pressure. 

Blows  delivered  upon  the  lower  chest,  especially  over 
the  cardiac  area,  produced  various  results.  In  one  case 
the  heart  was  instantly  arrested  from  the  effect  of  a  smart 
but  not  heavy  blow  from  a  small  hammer  over  the  car- 


38  EXPERIMENTAL   RESEARCH   INTO   THE 

diac  area,  and  death  at  once  ensued.  Respiratory  action 
was  as  suddenly  arrested.  The  most  common  result  was 
a  very  great  drop  in  the  blood -pressure, — a  collapse. 
Then  after  a  variable  time  the  heart  would  regain  its 
normal  action  and  the  lost  blood-pressure  would  be  re- 
covered. 

The  effects,  as  nearly  as  observations  would  permit  de- 
ductions, varied  in  different  dogs,  the  blow  being  deliv- 
ered with  about  the  same  force,  with  the  same  instrument, 
and,  as  nearly  as  may  be,  at  the  same  point  of  applica- 
tion. On  the  whole,  it  may  be  said  that  the  more  nearly 
the  blows  were  delivered  over  the  centre  of  the  area  of 
the  cardiac  dulness  the  greater  the  effect. 

Blows  delivered  upon  the  naked  heart  in  situ  produced 
like  results,  though  more  profound. 

The  evidence  thus  far  offered  tends  to  show  that  the 
solar  plexus  may  be  disregarded  as  a  factor,  and  that  the 
cause  of  the  striking  phenomena  is  the  mechanical  effect 
of  violence  upon  either  the  heart-muscle  itself  or  upon 
its  nerve-mechanism.  The  effect  might  have  been  in- 
duced by  a  "  vagal"  or  inhibitory  action.  If  so,  it  was 
either  a  direct  or  a  reflex  inhibition, — interpreting  direct 
inhibition  as  that  due  to  an  excitation  of  the  trunk  of 
the  vagus  or  its  cardiac  branches,  and  reflex  as  afferent 
impulses  sent  up  to  the  centre  in  the  medulla  from  irri- 
tation of  some  branch  of  the  vagus, — e.^.,  the  superior 
laryngeal. 

In  the  animals  in  which  both  vagi  had  been  previously 
severed,  when  the  foregoing  experiments,  blows,  etc., 
were  repeated,  like  results  were  produced.  The  collapse, 
then,  in  these  cases  could  not  be  due  to  reflex  inhibition, 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  39 

because  the  path  by  which  the  afferent  impulses  reach  the 
heart  had  been  severed. 

In  the  experiments  in  which  atropine  in  sufficient  dosage 
to  paralyze  the  terminals  of  the  vagi  in  the  heart  was 
given,  and  this  dosage  was  proved  by  applying  a  faradic 
current  from  a  Du  Bois-Reyrnond  apparatus  to  the  vagi 
while  the  secondary  coil  was  lapping  the  primary  by  half, 
upon  repeating  the  foregoing  experiments  like  results 
were  obtained,  though,  as  nearly  as  could  be  estimated, 
the  collapse  was  not  so  prolonged  as  before. 

Collapse  or  death  may  be  caused  wholly  indepen- 
dently of  the  vagi,  though  the  vagi  2)robably  slightly 
contribute  to  the  result. 

Finally,  collapse  or  death  from  violence  applied  upon 
the  lower  chest  or  abdomen  are  due  mainly  to  the  loss 
of  rhythmic  contractions  from  the  mechanical  irritation 
of  such  violence  on  the  heart-muscle  itself.  There  is 
evidence  tending  to  show  that  the  vagal  terminal  mech- 
anism in  and  near  the  heart  contributes  to  the  result,  but 
in  a  minor  degree. 

The  practical  deductions  are  sufficiently  obvious,  and 
need  not  be  here  repeated. 

EXPERIMENTAL    RESEARCH    INTO    THE    MECHANISM    OF 
DROWNING 

Prelifminary  Remarhs. — It  has  been  observed  that  in 
certain  cases  of  drowning  death  has  been  almost  instan- 
taneous, while  in  other  cases  a  considerable  time  has 
elapsed.  In  the  cases  of  sudden  drowning,  although  the 
body  may  be  immediately  recovered,  no  sign  of  life  re- 
mains.     This   research  was  undertaken   to  discover  an 


40  EXPERIMENTAL  RESEARCH   INTO   THE 

explanation  for  this  discrepancy  in  the  length  of  time 
before  death  occurs,  and  also,  if  possible,  to  throw  some 
light  upon  those  cases  of  sudden  death  in  good  swimmers, 
who  were  supposed  to  be  able  to  take  care  of  themselves 
in  the  water. 

In  the  jBrst  series  the  animals  were  wholly  submerged 
in  shallow  water  and  allowed  to  drown. 

In  a  second  group  of  experiments  the  trachea  was  en- 
tirely severed,  and  a  large  canula  tied  in  its  open  end ; 
to  this  canula  a  rubber  tubing  was  connected,  varying  in 
length  from  two  to  four  feet,  into  the  end  of  which  a 
funnel  was  attached.  With  this  apparatus,  by  pouring 
water  freely  into  the  funnel,  an  effect  could  be  produced 
fairly  comparable  with  that  of  submergence  in  water  to  a 
depth  equal  to  the  difference  between  the  level  of  the 
lungs  and  the  height  of  the  water  in  the  funnel. 

In  the  third  series  of  experiments  the  trachea  was 
severed,  the  animal  allowed  to  breathe  through  a  canula 
placed  in  the  trachea,  and  water  forced  through  the 
mouth  and  upper  air-passages,  but  not  reaching  the 
tracheo-pulmonary  tract. 

In  the  fourth  series  water  was  thrown  with  consider- 
able force  into  the  animal's  pharynx,  with  mouth  wide 
open  and  tongue  drawn  forward,  so  as  to  allow  direct 
contact  with  the  upper  air-passages,  the  trachea  remaining 
intact. 

In  the  fifth  series  preliminary  injections  of  physio- 
logic doses  of  atropine  were  made,  so  as  to  estimate  the 
part  played  by  the  vagi. 

In  the  sixth  series  both  vagi  were  severed,  preliminary 
to  the  drowning.     In  some  of  these  experiments  two  ani- 


SURGERY   OF  THE   RESPIRATORY   SYSTEM  41 

mals  were  simultaneously  drowned  under  different  con- 
ditions, so  that  comparisons  might  be  made. 

Protocols. — 1.  On  a  Bkye  terrier  twenty-one  pounds 
in  weight,  in  rather  j)Oor  condition,  with  control  blood- 
pressure  of  one  hundred  and  seventy-two  millimetres, 
under  ether  ansesthesia,  the  following  experiments  were 
performed  :  After  having  placed  the  respiratory  apparatus 
upon  the  chest  and  introduced  the  carotid  canula  to  mark 
the  blood-pressure  and  secure  a  good  control,  the  entire 
animal  was  submerged,  to  the  extent  of  merely  covering 
the  body,  in  water  at  97°  F.  There  was  some  fall  in  the 
blood-pressure  at  once ;  then  the  heart-beats  were  slowed, 
executing  long  strokes,  and  the  blood-pressure  rose  again 
to  the  height  it  was  in  the  control.  The  blood-pressure 
remained  at  this  height  during  forty-five  seconds.  Then 
it  gradually  fell,  the  heart-beats  became  slower  and  more 
shallow  until  death.  The  heart  continued  beating  nine 
minutes.  The  respirations  at  the  onset  of  this  submer- 
sion were  immediately  arrested ;  but  little  respiratory 
action  was  noted  during  the  first  twenty  seconds,  after 
which  there  were  powerful  respiratory  efforts  for  two  and 
one-half  minutes ;  then  the  respirations  became  less  pow- 
erful and  less  frequent,  gradually  decreasing,  and  failed 
before  the  heart  did. 

Autopsy. — The  intestines  were  very  much  congested 
and  in  slight  contraction.  The  venous  trunks  were 
everywhere  full.  The  right  auricle  was  greatly  dis- 
tended, the  right  ventricle  much  less  so ;  the  left  auricle 
was  full,  and  the  left  ventricle  empty  and  in  contraction. 
The  posterior  lobes  of  the  lungs  were  discolored,  and  on 
being  thrown  into  water  they  floated  low. 


42  EXPERIMENTAL  RESEARCH   INTO   THE 

2.  On  a  rat-terrier  weighing  fifteen  pounds,  with  con- 
trol blood-pressure  at  one  hundred  and  forty  millimetres, 
under  ether  anaesthesia,  the  following  exjDeriments  were 
performed :  The  preliminary  preparations  were  made  as 
in  the  preceding  case,  excepting  the  temperature  of  the 
water,  which  was  52°  F.  The  animal  lived  seven  min- 
utes. On  submersion  there  was  only  a  slight  immediate 
fall  in  blood-pressure,  then  there  followed  a  rise  to  a  point 
higher  than  the  control  pressure.  The  character  of  the 
heart-strokes  at  the  time  of  the  beginning  of  the  rise  was 
changed,  the  manometer  executing  sweeping  excursions 
with  a  slower  rhythm  than  in  the  control, — that  is  to  say, 
there  was  a  distinct  "  vagal"  action.  The  blood-pressure 
remained  at  this  elevated  level  for  two  minutes  and  fifty 
seconds,  then  it  declined  until  death.  In  this  experiment 
the  "  vagal"  character  of  the  heart-beats  was  the  prevail- 
ing characteristic.  The  respirations  at  first  were  very 
considerably  inhibited,  then  they  grew  stronger  between 
the  first  and  third  minutes,  after  which  they  became 
irregular,  slower,  and  weaker  until  death.  Respiratory 
and  cardiac  action  failed  almost  simultaneously. 

Autopsy. — The  posterior  lobes  of  the  lungs  displayed 
a  purplish  discoloration.  The  lungs  floated  on  being 
thrown  into  the  water,  although  they  floated  rather  low ; 
the  heart  was  in  diastole,  right  auricle  and  right  ventricle 
more  distended  than  the  left.  The  left  auricle  was  more 
distended  than  the  left  ventricle.  The  stomach  was  ex- 
tremely distended  with  air.  Venous  trunks  everywhere 
full ;  blood  dark. 

3.  On  a  mongrel  cur,  weighing  fifteen  pounds,  with  con- 
trol blood-pressure  at  one  hundred  and  ten  millimetres, 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  43 

under  chloroform  anaesthesia,  the  following  experiment 
was  performed,  as  nearly  as  possible  under  the  same  con- 
ditions as  in  the  preceding  case.  The  blood-pressure  on 
submersion  of  the  animal  remained  at  the  same  level. 
The  "  vagal"  beats,  as  above  described,  appeared  in  the 
latter  part  of  the  first  minute,  and  were  continued  until 
death.  In  the  third  minute  the  heart  ceased  beating 
temporarily,  but  in  ten  seconds  regained  its  beat  as  before. 
The  respirations  were  at  first  slowed,  then  temporarily 
arrested,  but  soon  began  a  vigorous  action,  reaching  the 
maximum  in  the  third  minute,  then  gradually  failing, 
the  animal  dying  in  seven  minutes. 

Autopsy.- — The  immediate  autoj^sy  revealed  the  heart 
in  diastole.  The  right  side  was  more  distended  than  the 
left ;  clots  in  both  sides.  The  venous  trunks  were  every- 
where full ;  the  arterial  system  almost  empty ;  intestines 
congested. 

4.  On  a  mongrel  weighing  twenty-four  pounds,  with 
control  blood-pressure  at  one  hundred  and  twenty  milli- 
metres, under  chloroform  anaesthesia,  the  same  experiment 
was  performed  as  in  the  preceding  case.  The  temperature 
of  the  water  in  this  case  was  50°  F.  The  animal  lived 
ten  minutes.  Immediately  on  submersion  there  was  a 
slight  rise  in  the  blood-pressure,  without  alterations  in 
the  character  of  the  heart-beats.  This  was  soon  followed 
by  a  marked  fall  in  the  blood -pressure  and  the  appear- 
ance of  "  vagal"  beats,  as  above  described.  The  fall, 
however,  was  but  slight,  and  during  the  first  five  minutes 
the  blood-pressure  was  well  sustained.  Later  in  the  ex- 
periment the  heart  showed  great  irregularity  in  its  action, 
executing  a  number  of  rather  rapid  strokes,  then  a  num- 


44  EXPERIMENTAL   RESEARCH   INTO   THE 

ber  of  extremely  slow  ones.  The  respirations  were  as 
gradually  slowed  and  became  quite  shallow,  then  they 
became  irregular,  and  later  on  were  followed  by  strong 
rapid  efforts,  these  finally  diminishing  in  both  force  and 
frequency  until  complete  cessation.  Respiration  stopped 
about  forty  seconds  before  the  heart  did. 

Autopsy. — Considerable  water  in  the  lungs,  slight  dis- 
coloration of  the  posterior  lobes,  the  heart  in  diastole, 
the  venous  system  full,  the  arterial  empty,  intestines  con- 
gested. 

5.  A  shepherd-dog,  weighing  forty-seven  pounds,  with 
control  blood-pressure  at  one  hundred  and  thirty  milli- 
metres, under  chloroform  anaesthesia,  with  the  water  at 
the  temperature  of  97°  F.  The  same  experiment  was 
performed  as  in  the  preceding  case,  with  practically  the 
same  results,  the  heart  beating  during  nine  minutes. 

Autopsy  revealed  conditions  similar  to  the  preceding 
case. 

In  the  following  group  of  experiments  the  animals  were 
drowned  by  introducing  water  into  the  pulmonary  tract 
through  the  trachea. 

6.  On  a  shepherd-dog  weighing  twenty  pounds,  under 
ether  ansesthesia,  the  following  experiment  was  performed  : 
The  trachea  was  dissected  out  and  severed  just  below  the 
cricoid.  Into  the  free  end  a  canula  was  inserted  and 
closely  tied ;  to  the  canula  rubber  tubing  was  attached, 
and  after  control  tracings  had  been  secured,  the  free  end 
of  the  tube  was  immersed  in  water  at  a  temjDerature  of 
128°  F.  There  was  a  direct  fall  of  fifteen  millimetres  in 
the  blood-pressure  after  the  first  inspiratory  effort.  The 
respirations  were   shallow  and    slowed.      The   tube  was 


SURGP]RY   OF   THE   RESPIRATORY   SYSTEM  45 

kept  under  the  water  for  twenty  seconds,  and,  when  re- 
moved, the  animal  rapidly  regained  the  lost  depression. 
The  same  process  was  again  repeated  during  twenty 
seconds,  with  the  same  results.  The  process  was  four 
times  repeated,  and  practically  the  same  results  followed. 
It  was  found  that,  if  the  experiments  were  continued 
until  the  blood-pressure  became  quite  low,  and  if  the 
animal  were  allowed  to  breathe  air  again,  the  blood- 
pressure  would  rapidly  recover. 

Autopsy. — The  chest  was  at  once  opened ;  the  venous 
trunks  were  all  much  distended,  the  right  side  of  the 
heart  full,  the  left  side  contracted.  The  blood  clotted 
very  quickly ;  veins  in  the  splanchnic  area  distended ; 
all  the  blood  dark. 

7.  On  a  spaniel  weighing  twenty-two  pounds,  with  con- 
trol blood-pressure  at  one  hundred  and  forty  millimetres, 
under  ether  anaesthesia,  the  following  experiments  were 
performed :  With  the  preliminary  preparation  the  same 
as  in  the  preceding  case,  the  tube  was  again  placed  under 
water  and  the  dog  allowed  to  breathe  nothing  but  water 
for  one  minute.  There  was  an  immediate  fall  in  blood- 
pressure,  after  which  there  was  a  compensatory  rise,  with 
exhibition  of  long  strokes.  On  allowing  the  animal  to 
breathe  air,  the  blood-pressure  curve  again  recovered 
itself.  The  resiDirations  at  first  were  temporarily  arrested, 
then  became  shallow  and  irregular,  but  finally  grew  more 
powerful  and  more  frequent.  This  experiment  in  almost 
every  detail  resembled  the  preceding. 

The  autopsy  showed  the  venous  trunks  everywhere  dis- 
tended, the  right  side  of  the  heart  full,  the  left  side  empty, 
blood  very  dark. 


46  EXPERIMENTAL   RESEARCH   INTO   THE 

8.  On  a  skye  terrier,  weighing  twenty-two  pounds,  with 
control  pressure  at  one  hundred  and  fifty-four  millimetres, 
under  ether  anaesthesia,  the  following  experiment  was  per- 
formed :  To  the  end  of  the  rubber  tubing  three  feet  long 
a  large  funnel  was  attached,  and  into  this  funnel  water 
was  poured  at  a  temperature  of  148°  F.,  so  as  to  keep 
more  or  less  water  in  the  funnel  all  the  time.  There  was 
a  momentary  sharp  rise  in  the  blood-pressure ;  this  was 
followed  by  a  sharp  decline  of  ten  millimetres,  then  a 
sudden  drop,  almost  to  the  abscissa  line  of  the  central 
blood-pressure.  After  this  sudden  drop,  which  was  ac- 
complished within  five  seconds,  there  was  after  thirty 
seconds  a  compensatory  rise  in  the  blood-pressure,  but 
the  heart-beats  had  practically  ceased  at  the  end  of  sixty 
seconds.  The  compensatory  rise  was  but  small  in  com- 
parison with  the  great  fall.  The  heart-beats  that  appeared 
after  the  animal's  collapse  were  slow  and  feeble,  the  res- 
pirations were  instantly  temporarily  arrested,  but  after 
from  ten  to  thirty  seconds  they  were  renewed  and  con- 
tinued to  increase  in  amplitude  for  about  thirty  seconds, 
when  they  rather  rapidly  ceased.  The  animal  was  practi- 
cally dead,  so  far  as  may  be  estimated  from  a  total  col- 
lapse of  the  blood-pressure,  within  five  seconds  after  the 
water  had  filled  the  lungs  and  the  rubber  tubing. 

Autopsy. — An  immediate  autopsy  showed  the  venous 
trunks  greatly  distended,  the  right  side  of  the  heart  full 
to  over-distention,  the  left  side  of  the  heart  empty  and  con- 
tracted, the  blood  very  dark. 

9.  On  a  mongrel  weighing  fourteen  and  one-half 
pounds,  with  control  blood-pressure  at  one  hundred  and 
forty  millimetres,  under  ether  anaesthesia,  the  following 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  47 

experiment  was  performed :  The  technic|ue  of  the  pre- 
ceding case  was  carried  out  in  every  detail,  with  the  ex- 
ception that  the  water  was  introduced  at  a  temperature  of 
36°  F.  In  this  case  there  was  a  momentary  sudden  rise 
in  pressure,  then  a  very  considerable  fall,  lasting  during 
five  seconds,  after  which  there  was  a  great  collapse  in  the 
blood-^^ressure,  which  sank  almost  immediately  to  the 
abscissa  line.  The  cardiac  action  after  this  short  time  was 
represented  by  a  few  feeble  strokes.  The  circulation  after 
the  lapse  of  these  few  seconds  was  completely  arrested. 
As  to  respiration,  there  were  five  slow  respiratory  efforts, 
then  for  seven  seconds  there  was  no  respiration  at  all,  and 
afterwards  the  respiratory  efforts  were  slow,  diminished  in 
amplitude,  and  at  the  end  of  fifty-six  seconds  entirely 
ceased.  During  the  following  two  minutes  there  were 
occasionally  gasping  respiratory  efforts. 

Autopsy. — Immediate  autopsy  showed  all  the  venous 
trunks  full,  arteries  quite  empty,  right  side  of  the  heart 
extremely  distended,  left  side  empty  and  contracted. 

10.  On  a  mongrel  cur  weighing  twenty-four  pounds, 
with  control  pressure  at  one  hundred  and  twenty-eight 
millimetres,  under  ether  anaesthesia,  arranged  as  in  the 
preceding  case,  a  similar  experiment  was  performed,  hold- 
ing the  funnel  at  the  same  height  as  before.  After  the 
water  began  to  flow  the  heart  was  slowed  during  ten 
beats ;  during  this  time  there  was  a  considerable  fall  in 
the  blood-pressure,  then  there  was  a  collapse  during  four 
seconds,  approaching  nearly  to  the  abscissa  line.  This 
striking  fall  was  most  noted  during  the  respiratory  efforts. 
During  expiration  the  blood-pressure  rose  considerably ; 
during  inspiration  it  correspondingly  fell.     Kespirations 


48  EXPERIMENTAL   RESEARCtI   INTO   THE 

were  at  first  slowed  and  more  shallow,  afterwards  greatly 
slowed,  with  strong,  continued  expiratory  efforts.  Res- 
pirations, however,  stopped  almost  simultaneously  with 
the  heart.  The  animal  was  practically  dead  at  the  end 
of  nine  seconds. 

Autopsy. — An  immediate  examination  showed  the 
venous  trunks  distended,  the  right  side  of  the  heart  full 
and  flaccid,  left  side  empty  and  contracted. 

11.  On  a  bull-dog  weighing  forty-four  pounds,  in  good 
health,  with  control  blood-pressure  at  one  hundred  and 
fifty-five  millimetres,  under  ether  ansesthesia,  with  condi- 
tions the  same  as  in  the  preceding  case,  the  following 
phenomena  were  observed.  After  the  water  began  to  flow 
into  the  lungs  there  were  five  sweeping  heart-beats,  during 
which,  after  a  momentary  rise,  there  was  a  considerable 
fall  in  the  blood-pressure,  and  after  these  five  beats  had 
been  executed  there  was  a  collapse  in  the  blood-pressure. 
This  great  collapse  occurred  during  the  inspiratory  phase 
of  respiration.  After  a  lapse  of  a  short  time  there  was  a 
slight  comj)ensatory  rise  in  the  pressure;  this  rise  was 
comparatively  small.  The  respirations  at  first  were 
slowed,  then  became  more  feeble  and  less  frequent  until 
death. 

Autojjsy. — An  immediate  examination  showed  the  ve- 
nous trunks  distended,  the  right  side  of  the  heart  full 
and  flaccid ;  the  auricle  was  more  distended  than  the 
ventricle,  the  left  side  empty  and  contracted. 

12.  On  a  water-spaniel  weighing  twenty-eight  pounds, 
in  fair  health,  with  control  blood-pressure  at  one  hundred 
and  forty-two  millimetres,  under  ether  anaesthesia,  the 
preceding  experiment  was  repeated.     The  blood-pressure 


SURGERY   OF  TFIK   RKSI'TJIATORY   SYSTEM  49 

curve  showed  all  the  characteristics  displayed  by  the  pre- 
ceding case,  excepting  the  collapse  was  not  so  sudden  and 
the  compensatory  rise  was  greater.  Death,  however,  oc- 
curred within  a  few  seconds.  The  respiratory  phenomena 
were  practically  the  same  as  in  the  preceding  experiment. 
At  the  autopsy,  the  venous  trunks  were  all  distended, 
the  blood  was  extremely  cyanotic,  the  right  side  of  the 
heart  full  and  flaccid,  especially  the  right  auricle,  the  left 
side  empty  and  contracted. 

13.  On  a  nineteen-and-one-half-pound  mongrel,  with 
control  blood-pressure  of  one  hundred  and  fifty-four  milli- 
metres, under  ether  anaesthesia,  under  conditions  similar 
to  the  preceding,  and  with  the  same  technique,  results 
were  obtained  in  almost  every  respect  similar,  excepting 
that  the  respirations  were  more  nearly  completely  arrested 
at  the  onset.  There  was  again  the  same  collapse  in  the 
blood-pressure  and  the  quick  death. 

Autopsy. — An  immediate  examination  showed  the  ve- 
nous trunks  distended,  the  right  side  of  the  heart  full  and 
flaccid,  left  side  empty  and  contracted.  The  lungs,  when 
thrown  into  water,  floated  low. 

14.  On  a  forty-seven-and-one-half-pound  bull-dog,  with 
control  blood-pressure  at  one  hundred  and  forty-five  mil- 
limetres, under  ether  anaesthesia,  and  according  to  the 
technique  before  described,  a  like  experiment  was  per- 
formed with  the  results  essentially  .the  same,  although 
difiering  in  the  following  details :  After  the  great  col- 
lapse there  was  a  compensatory  rise  in  blood-pressure 
during  the  second  minute,  almost  reaching  the  control 
height.  However,  this  blood-pressure  curve  was  greatly 
modified  by  each  respiratory  gasp.     Respirations  were  at 


50  EXPERIMENTAL  RESEARCH   INTO   THE 

first  arrested,  and  later  irregular  respiratory  efforts  were 
noted. 

The  autopsy  immediately  after  death  showed  all  the 
venous  trunks  full,  arteries  empty,  right  side  of  the  heart 
full,  left  side  empty  and  contracted,  the  liver  much  dis- 
tended. 

15.  Upon  a  spaniel,  weighing  thirty  pounds,  with  con- 
trol pressure  at  one  hundred  and  sixty-four  millimetres, 
under  ether  anaesthesia,  the  previous  technique  was  re- 
peated. After  the  first  momentary  rise  in  the  blood- 
pressure  there  was  a  considerable  fall,  then  great  collapse, 
after  which  there  was  a  compensatory  partial  recovery, 
then  a  gradual  decline  until  death.  The  respirations 
were  slow  and  shallow,  afterwards  somewhat  increased, 
then  they  gradually  declined  until  death.  At  the  end  of 
four  minutes  and  ten  seconds  no  further  respiratory  or 
cardiac  activity  could  be  noticed,  although  the  animal 
was  practically  dead  within  twenty  seconds. 

Autopsy  showed  all  the  veins  full,  the  arteries  empty, 
the  blood  cyanotic,  right  side  of  the  heart  very  full, 
especially  the  right  auricle.  The  left  side  contained  a 
little  blood,  but  was  fairly  well  contracted. 

16  and  17.  A  double  experiment,  in  which  the  same 
technique  as  in  the  preceding  case  was  carried  out.  In 
one  animal  water  at  33°  F.  and  in  the  other  at  180°  F. 
was  used.  For  the  cold-water  experiment  a  fourteen- 
and-one-half-pound  spaniel,  with  control  blood-pressure 
at  one  hundred  and  twenty  millimetres,  under  ether, 
was  employed.  For  the  hot- water  experiment  use  was 
made  of  a  thirteen-and-one-half-pound  mongrel,  with 
carotid  blood-pressure  at  one  hundred  and  twenty  milli- 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  51 

metres,  also  under  ether.  The  animals  were  both  drowned 
in  the  same  way  and  at  the  same  time,  with  the  funnels 
at  the  same  height.  In  the  cold-water  experiment  there 
was  at  first  a  rapid  slight  drop  in  the  blood-pressure,  fol- 
lowed by  "  vagal"  beats,  reaching  a  considerable  height. 
Then  there  was  a  very  rapid  fall,  the  heart  executing 
rather  faint  beats,  at  fairly  regular  intervals,  during  five 
minutes  and  twenty  seconds.  Respiratory  efforts  were 
slow  and  soon  failed.  In  the  hot-water  experiment  the 
blood-pressure  fell  immediately  to  zero,  then  there  were 
thirteen  strong  "  vagal"  beats,  a  few  very  weak  ones,  then 
death.  The  last  observable  action  of  either  the  heart  or 
the  respiration  was  at  the  end  of  two  minutes. 

The  autopsies  in  both  cases  revealed  similar  condi- 
tions, excepting  with  regard  to  the  contraction  of  the 
heart.  In  the  hot-water  dog  the  heart  was  so  firmly  con- 
tracted as  to  give  the  impression  that  the  protoplasm  was 
coagulated. 

18  and  19.  A  double  experiment,  with  the  technique 
as  in  the  preceding  case,  using  in  the  one  dog  water  at 
170°  F.  and  in  the  other  water  at  36°  F.  For  the  hot- 
water  experiment  the  animal  used  was  a  thirty-seven- 
pound  Scotch  collie,  with  control  blood-pressure  at  one 
hundred  and  sixty  millimetres.  The  cold-water  dog  was 
a  mongrel,  weighing  twenty-three  pounds,  with  control 
blobd-pressure  at  one  hundred  and  forty  millimetres. 
Both  were  under  ether  anaesthesia.  Both  were  drowned 
at  the  same  time  and  by  the  same  method.  At  the  end 
of  two  minutes  and  ten  seconds  neither  cardiac  nor 
respiratory  action  appeared  in  the  hot-water  dog,  whilst 
in  the  cold-water  dog  these  functions  continued  for  seven 


52 


EXPERIMENTAL   RESEARCH   INTO   THE 


minutes  and  thirty  seconds.  In  both  cases  there  was  the 
usual  great  fall  in  the  blood-pressure.  In  the  hot-water 
dog  the  fall  amounted  to  a  striking  collapse,  rather  more 
than  in  the  cold-water  experiment.  However,  the  fall  in 
each  case  was  very  sudden  and  great. 


12.  Double  Drowning  Experiment.— The  upper  tracing  represents  the  respiration  in  the 
hot-water  (170°  F.)  experiment,  tlie  next  tracing  the  blood-pressure  of  the  same.  The  third 
tracing  represents  the  blood-pressure  in  the  cold-water  i36°  F.i  experiment,  and  the  fourth 
the  respiration  of  the  same.    The  lower  two  are  the  signal  and  the  lime  marks  (seconds). 

At  the  autopsies  the  only  difference  was  that  in  the 
hot-water  dog  the  heart  was  firmly  contracted  in  every 
chamber ;  in  the  cold-water  dog  the  left  side  was  but 
moderately  contracted,  while  the  remainder  of  the  heart 
was  flaccid. 

20  and  21.  A  double  experiment,  under  all  the  condi- 
tions as  in  the  preceding  case,  the  cold-water  dog  im- 


SURGEllY    OF   TIIK    IMISI'I  IIATOHV    SYSTEM  53 

mersed  in  33°  F.  water,  the  liot- water  dog  at  MO'^  F.  For 
the  cold-water  dog,  a  St.  Bernard,  weighing  sixty-eight 
pounds,  with  control  blood -pressure  at  one  hundred  and 
forty-four  millimetres,  was  used ;  for  the  hot-water  dog, 
a  Newfoundland,  weighing  ninety  pounds,  with  control 
blood-pressure  of  one  hundred  and  fifty  millimetres. 
Both  animals  were  drowned  simultaneously  by  like 
methods.  In  the  cold-water  experiment  there  were  more 
or  less  respiratory  and  cardiac  efforts  for  thirteen  min- 
utes. In  the  hot-water  experiment  the  cardiac  and  the 
respiratory  efforts  continued  ten  minutes.  This  experi- 
ment in  almost  every  respect  was  similar  to  the  pre- 
ceding, the  greater  drop  in  the  blood-pressure  appearing 
in  the  hot-water  dog,  with  the  compensatory  rise  later. 
In  both  cases  the  circulatory  apparatus  was  practically 
arrested  within  the  first  ten  seconds. 

At  the  autopsies  the  one  important  difference  between 
the  two  dogs  was  the  condition  of  the  heart.  The  right 
side  of  the  heart  in  each  dog  was  distended,  especially 
the  right  auricle.  The  left  side  of  the  heart  in  the  cold- 
water  dog  was  flaccid,  and  in  the  hot-water  dog  it  was 
firmly  contracted.  The  left  auricle  also  was  firmly  con- 
tracted. 

22  and  23.  A  double  experiment  with  two  animals, 
each  weighing  sixteen  pounds,  in  good  condition,  and 
each  having  a  control  blood-pressure  at  one  hundred 
and  thirty  millimetres.  Both  were  under  ether  anaes- 
thesia. Both  dogs  were  drowned  with  water  at  the  tem- 
perature of  the  body.  The  second  dog,  which  we  shall 
name  the  "vagal"  dog,  was  subjected  to  dissection  of  both 
vagi  preliminary  to  the  drowning.     The  usual  effect,  in- 


54  EXPERIMENTAL   RESEARCH   INTO   THE 

creased  height  in  blood-pressure,  was  noted  on  severing 
the  vagi.  At  the  same  time  respiratory  movements  were 
decreased  in  frequency  and  increased  in  amplitude.  Both 
dogs  were  drowned  at  the  same  time  and  in  the  same 
manner.  The  animal  with  intact  vagi  died  displaying 
almost  the  precise  phenomena  described  in  the  preceding 
cases.  The  "  vagal"  dog  suffered  a  fall  in  blood-pressure 
quite  equal  to  the  control  dog  and  died  within  two  min- 
utes. It  was  observed,  however,  that  the  respirations 
were  not  arrested  temporarily  so  markedly  as  in  experi- 
ments in  which  the  vagi  were  intact,  but  respirations 
went  on  for  twenty  seconds,  then  gradually  faded  out. 

Autopsy. — The  autopsy  showed  conditions  entirely  sim- 
ilar to  those  in  the  preceding  experiments  in  which  water 
at  the  temperature  of  the  body  had  been  employed. 

24  and  25.  Double  experiment.  The  first  animal  was 
a  control,  weighing  twenty-six  pounds,  in  good  condition, 
with  blood-pressure  at  one  hundred  and  thirty  milli- 
metres. In  the  second  animal  a  physiological  dose  of 
atropine  was  administered  previous  to  the  experiment. 
The  effectiveness  of  the  atropine  was  tested  by  stimula- 
tion with  a  Du  Bois-Reymond  coil.  Both  animals  were 
then  drowned  in  the  same  way  with  the  same  apparatus. 
The  control  dog  exhibited  nearly  all  the  phenomena  that 
have  been  heretofore  described  in  similar  experiments. 
In  the  atropine  experiment  the  collapse  of  the  blood- 
pressure  was  not  so  marked  as  in  the  control.  The  fall 
of  the  pressure,  however,  was  very  great.  The  respira- 
tory phenomena  in  the  atropine  experiment  were  similar 
to  those  in  the  control. 

The   autopsy   revealed   the   auricles  of    both   animals 


SURGERY   OF  THE   RESPIRATORY   SYSTEM  55 

practically  in  the  same  condition  as  in  the  preceding 
cases,  excepting  in  the  atropine  experiment  the  blood  was 
more  clotted  than  in  the  control.  The  autopsies  were 
made  simultaneously. 

26  and  27-  Double  experiment.  For  a  control  a  mon- 
grel, weighing  twenty-six  pounds,  with  a  blood-pressure 
of  one  hundred  and  twenty-three  millimetres,  was  used. 
For  the  "  vagal"  a  dog,  weighing  twenty-two  pounds, 
with  one  hundred  and  twenty  millimetres.  Ether  was 
administered  in  both  cases.  On  severing  the  vagi  the 
usual  phenomena  followed.  Both  dogs  were  drowned 
simultaneously.  The  blood-pressure  curve  in  each  case 
was  smaller,  although  in  the  "  vagal"  the  heart-beats 
were  more  rapid,  whilst  in  the  control  the  heart  exe- 
cuted the  usual  slow,  strong  beats.  The  immediate 
effects  upon  the  respiration  differed  in  these  animals. 
In  the  control  the  respirations  were  immediately  arrested, 
then  became  slowed,  but  in  the  "vagal"  dog  the  respi- 
rations were  not  so  markedly  interfered  with,  gradually 
declined  in  their  amplitude,  and  later  in  their  frequency, 
until  death. 

The  autopsy  showed  the  u.sual  conditions. 

28  and  29.  Double  experiment.  For  a  control  dog,  a 
Skye  terrier,  twenty-one  pounds  in  weight,  blood-pressure 
at  one  hundred  and  seventy  millimetres,  was  used.  For 
the  ''  vagal"  dog,  a  mongrel,  weighing  twenty-two  pounds, 
blood-pressure  one  hundred  and  forty  millimetres,  was 
selected.  Both  animals  were  drowned  under  the  same 
conditions  as  in  the  preceding  cases,  and  simultaneously. 
On  severing  the  vagi  the  usual  phenomena  occurred, — 
namely,  a  rise  in  blood-pressure,  with  increase  in  the  fre- 


56  EXPERIMENTAL  RESEARCH   INTO   THE 

quency  of  the  heart's  action,  and  slowed,  deepened  respi- 
ratory action.  The  initial  fall  in  both  cases  was,  in  the 
main,  the  same ;  the  animals  lived  about  the  same  length 
of  time,  but  the  respiratory  effects  differed  in  this  respect, 
that  while  in  the  control  dog  the  respirations  were  imme- 
diately arrested,  then  later  partially  resumed,  in  the 
"vagal"  the  respirations  were  not  immediately  affected, 
but  gradually  declined  until  death. 

Autopsy  revealed  conditions  similar  to  those  observed 
in  the  preceding  cases,  excepting  that  in  the  control  dog 
the  heart  was  more  distended  than  in  the  "  vagal." 

30  and  31.  Double  experiment.  The  first  animal  was 
given  a  physiologic  dose  of  atropine,  and  in  the  second 
both  vagi  were  cut.  The  animals  weighed  respectively 
twenty-one  and  twenty-two  pounds,  with  blood-pressure 
at  one  hundred  and  ten  and  one  hundred  and  fifteen  mil- 
limetres. Both  were  under  ether  anaesthesia.  Both  ani- 
mals were  drowned  simultaneously  in  the  same  manner. 
In  all  the  main  respects  the  blood-pressure  exhibited  like 
phenomena  in  both  animals  ;  the  respirations,  however, 
in  the  atropine  experiment  were  more  directly  affected, 
having  been  arrested  immediately ;  then  very  slow,  shal- 
low efforts  were  observed ;  while  in  the  "  vagal"  experi- 
ment respirations  were  not  immediately  affected,  but  went 
on  for  a  number  of  sti'okes  in  a  rhythmic  way,  and 
finally  ceased. 

The  autopsy  showed  similar  conditions  in  every  detail. 

In  the  following  experiments  the  animals  were  sub- 
jected to  a  stream  of  water  forced  into  the  mouth  and 
through  the  upper  air-passages  alone,  excluding  the 
trachea  and  respiratory  tract. 


SURGERY   OF   THE   RESPIRATORY   SYSTEM 


57 


32.  A  shepherd-dog,  weighing  tliirty  j)Oun(ls,  with 
blood-pressure  at  one  hundred  and  forty-two  millimetres, 
was  subjected  to  the  following  technique  :  The  trachea 
was  dissected  out,  severed  from  the  larynx,  and  a  breath- 
ing apparatus  attached.  The  animal's  mouth  was  then 
opened  and  a  stream   of  water  was  forced  through  the 


w***'^^ 


13.  Effect  of  dieecting  a  Spray  of  Water  forcibly  into  the  Pharynx  while  the 
Tongue  was  well  depressed.— The  upper  tracing  represents  the  respiration,  the  next  the 
blood-pressure,  and  the  lower  two  the  signal  and  the  time-marker  respectively. 


pharynx  into  the  larynx.  The  effect  upon  the  blood- 
pressure  was  a  slight  fall,  the  heart  executing  extremely 
long  "  vagal"  strokes ;  then  slow,  sweeping  beats,  charac- 
teristic of  such  action,  appeared.  The  respirations  were 
momentarily  arrested,  after  which  they  went  on  undis- 
turbed.   This  experiment  was  repeated  a  number  of  times. 


58  EXPERIMENTAL   RESEARCH   INTO   THE 

each  time  producing  similar  results,  though  subsequently 
the  results  were  not  so  striking.  The  animal  was  then 
killed  by  pouring  water  into  its  trachea  through  the  fun- 
nel, as  in  the  preceding  cases,  exhibiting  all  the  charac- 
teristic phenomena. 

The  observations  at  the  autopsy  were  the  same  as  in 
the  preceding  experiments. 

33.  The  technique  of  the  preceding  experiment  was 
carried  out  in  every  detail,  yielding  like  results.  Water 
at  different  temperatures  was  used.  It  was  found  that 
more  striking  results  were  obtained  by  using  hot  water 
than  when  the  water  was  at  the  temperature  of  the  body. 
The  greater  the  force  of  the  stream,  the  more  marked  the 
alteration  in  the  heart-strokes.  Both  vagi  were  then 
severed,  and,  on  repeating  the  experiment,  the  heart-beat 
was  not  altered. 

34.  In  this  experiment  the  same  technique  was  carried 
out  as  in  33,  with  practically  the  same  results. 

Summary. — The  experimental  evidence  obtained  would 
seem  to  establish  an  important  factor  in  the  effect  uj)on 
the  circulation  from  mechanic  pressure  of  the  column  of 
water  in  drowning.  When  the  animal  was  barely  sub- 
merged in  water  the  effect  upon  the  blood-pressure  was 
not  nearly  so  great,  the  usual  marked  collapse  did  not 
appear,  and  the  animal  lived  longer.  Not  only  did  the 
circulatory  apparatus  maintain  its  integrity  longer,  but 
the  respiratory  as  well.  Although  not  noted  in  the  pro- 
tocols, in  a  number  of  instances  the  height  of  the  tubing 
through  which  the  water  was  poured  was  varied,  and 
with  this  variation,  as  nearly  as  could  be  estimated,  there 
was  a  comparative  diminution   or   increase,  as  the  case 


SURGERY   OF  THE   RESPIRATORY   SYSTEM  59 

might  be,  in  the  extent  of  tlie  collapse  in  the  hloorl- 
pressure, — that  is  to  say,  in  a  given  case,  tlie  higher  the 
column  of  water,  the  greater  the  collapse  in  the  l)loo(l- 
pressure. 

Now,  throughout  the  experiments  it  will  be  noted  that 
the  respiratory  action  was  rather  summarily  arrested ; 
after  a  pause,  or  at  least  after  a  period  of  very  slight 
activity,  the  respirations  became  gradually  stronger  and 
then  faded  away ;  all  of  which,  as  a  rule,  occurred  during 
the  period  of  from  thirty  seconds  to  several  minutes.  The 
circulation  was  in  nearly  every  experiment  wholly  over- 
come within  fifteen  seconds,  and  in  a  goodly  number  of 
cases  within  from  five  to  ten  seconds.  The  collapse  was 
most  marked  during  the  inspiratory  phase  of  respiration. 
The  effect  of  respiratory  action  upon  the  blood-pressure 
was  most  marked,  producing,  as  it  did,  extreme  variations 
in  the  blood-pressure  curve.  These  variations  seemed  to 
be  rather  out  of  proportion  to  the  force  of  the  exj^iratory 
action. 

Now,  in  what  respect  do  these  phenomena  correspond 
with  the  phenomena  of  asphyxia  ?  In  asphyxia  there  is 
not  a  sudden  cessation  of  either  the  respiratory  or  the 
cardiac  activity.  When  the  exchange  of  air  is  suddenly 
arrested,  as  by  clamping  the  trachea,  respirations  may 
momentarily  cease,  but  this  cessation  is  only  momentary, 
and  respiratory  efibrts  are  carried'  on  with  increasing 
vigor  for  a  considerable  length  of  time.  The  respiratory 
curve  is  far  greater  and  more  vigorous  in  an  asphyxia 
experiment  than  in  the  drowning  experiments. 

As  to  the  circulatory  phenomena :  In  asphyxia  there 
may  be  a  temporary  decline — usually  a  slight  decline — in 


60  EXPERIMENTAL  RESEARCH   INTO   THE 

the  blood-pressure.  This  decline  is  very  quickly  recov- 
ered from,  and  there  is  an  actual  rise  in  the  blood-pressure 
above  the  level  at  which  it  was  before  the  asphyxia  was 
induced.  The  heart  continues  to  beat  in  asphyxia  for  as 
long  as  from  three  to  twelve  minutes.  In  fresh  animals, 
as  were  those  in  which  drowning  experiments  were  per- 
formed, the  blood-pressure  in  asphyxia  never  underwent 
this  fall;  on  the  contrary,  as  it  was  said  before,  in  as- 
phyxia it  rose.  The  characteristics  of  the  blood-pressure 
curve  in  asphyxia  are  an  immediate  gradual  temporary 
decline,  then  a  gradual  rise  above  the  height  it  was  be- 
fore the  experiment;  late  in  the  experiment,  there  will 
appear  Traube-Hering  curves,  and  finally  the  heart  ceases 
beating  in  diastole.  It  is  true  that  in  producing  asphyxia, 
either  by  drowning  or  by  closing  the  trachea,  there  is  no 
exchange  of  gases  in  the  lungs.  There  is  an  immediate 
cutting  off  of  the  supply  of  oxygen.  On  what  grounds, 
then,  may  the  very  great  difference  between  the  phe- 
nomena of  these  two  conditions  be  explained  ?  It  cannot 
be  a  reflex  action  through  the  vagi,  producing  a  powerful 
inhibition  upon  the  heart  and  upon  the  respirations ; 
for  in  the  experiments  in  which  the  vagi  were  cut,  pre- 
liminary to  the  drowning,  as  striking  a  collapse  in  the 
blood-pressure  occurred  as  before.  This,  in  itself,  is  con- 
clusive so  far  as  the  trunks  of  the  vagi  are  concerned ; 
but  it  may  be  argued  that  some  influence  upon  the  ter- 
minals of  the  vagi  may  cause  inhibition  of  the  heart. 
In  a  series  of  experiments  in  which  atropine  was  given 
previous  to  the  experiment,  in  dosage  sufficient  to  para- 
lyze the  nerve-endings  in  the  heart,  as  proved  by  laying 
the  electrode  of  a  Du  Bois-Keymond  apparatus  upon  the 


SURGERY    OF   TFIE    RES1>II{AT()RY   SYSTKM  (Jl 

vagus,  producing  no  inhibition  while  the  secondary  coil 
was  lapping  the  primary  by  one-half,  when  the  usual 
drowning  experiment  was  then  performed,  the  collapse 
in  blood-pressure  occurred  the  same  as  in  the  cases  in 
which  the  animal  had  not  received  this  drug.  There 
is  no  other  mechanism,  then,  through  which  afferent 
impulses  may  produce  an  inhibitory  action  upon  the 
heart,  producing  thereby  such  staggering  fall  in  blood- 
pressure  ;  and,  besides,  the  character  of  the  heart-beats 
at  the  moment  of  the  great  staggering  fall  in  blood- 
pressure  is  not  that  of  a  "  vagal"  beat.  Then  is  it  j)os- 
sible  that  the  presence  of  water  in  the  lungs  may  cause 
a  stimulation  of  vasomotor  nerves  producing  these  effects  ? 
In  the  first  place,  it  is  impossible  to  produce  so  abrupt 
and  staggering  a  fall  by  acting  u^Don  all  the  vaso-motors 
of  the  body  at  once.  Much  less  would  it  be  possible  to 
account  for  such  fall  in  the  blood-pressure  by  supposing 
the  vaso-motors  supplying  the  blood-vessels  in  the  lungs 
to  be  stimulated.  At  best  the  vasomotors  supplying  the 
lungs  are  not  capable  of  producing  great  alterations  in 
the  blood-pressure. 

Then,  may  it  be  due  to  the  temperature  of  the  water  ? 
A  series  of  double  experiments  was  made  in  which  the 
water  introduced  into  one  animal  was  hot,  while  another 
animal  was  drowned  simultaneously  with  cold  water ;  the 
fall  in  both  cases  was  practically  the  same.  The  animal 
taking  the  hot  water  showed  total  loss  of  cardiac  and 
respiratory  activity  earlier  than  the  animal  taking  the 
cold  water.  However,  the  feeble  efforts  after  the  first 
fifteen  seconds  in  either  case  were  not  sufiicient  to  re- 
establish either  the  circulation  or  the  respiration.     In  a 


62  EXPERIMENTAL   RESEARCH   INTO   THE 

further  series  of  cases,  in  which  the  water  was  introduced 
at  the  temperature  of  the  body,  the  phenomena  did  not 
essentially  differ  from  the  phenomena  in  the  experiments 
in  which  the  water  was  used  either  hot  or  cold.  While 
in  some  respects  the  temperature  of  the  water  had  char- 
acteristic effects,  these  characteristic  effects  were  more 
marked  in  the  case  of  hot  water,  and  were  shown  on 
necropsy  in  the  firm  contraction  of  the  heart.  The  left 
auricle  was  most  firmly  contracted,  and  the  left  ventricle 
next. 

Then,  if  this  striking  collapse  in  the  blood-pressure  is 
not  due  to  the  temperature  of  the  water,  to  a  vasomotor 
disturbance,  nor  to  an  excitation  of  the  vagi  or  any  of 
their  terminals,  nor  to  the  asphyxia  effects,  to  what  may 
these  phenomena  be  attributed?  Before  proposing  an 
explanation  it  would  be  well  to  call  attention  to  some  esti- 
mation of  the  comparative  value  of  this  staggering  fall  in 
the  blood-pressure.  In  order  to  make  a  comparative  esti- 
mate the  superior  vena  cava  and  inferior  vena  cava  were 
severed,  letting  free  torrents  of  blood,  producing  thereby 
as  staggering  a  fall  in  blood-pressure  as  is  possible  to  do 
by  hemorrhage.  Even  when  severing  the  one  and  leaving 
the  other  intact,  the  collapse  in  blood-pressure  was  not  so 
great  as  that  in  the  drowning  experiments. 

Whatever  may  be  the  mechanism  of  this  sudden  col- 
lapse in  drowning,  it  must,  to  a  very  extraordinary  degree, 
block  the  entire  circulation.  Now,  the  circulation  in  the 
lungs  is  not  under  a  high  pressure ;  especially  in  the  cap- 
illaries, there  is  not  much  resistance  to  overcome  in  this 
circulation.  Without  undertaking  to  state  the  exact 
pressure,  it  was  calculated  that  in  all  the  experiments 


SURGEKY    OK   THE   JIKSIMRATORY    SYSTEM  68 

in  which  there  was  a  collapse  in  the  blood-pressure,  the 
column  of  water  in  the  tube  in  the  apparatus  exerted  a 
pressure  greater  than  the  capillary  pressure  in  the  lungs. 
So  that  as  long  as  the  apparatus  was  filled  with  water  a 
pressure  was  exerted  indirectly,  through  the  medium  of 
the  air  filling  the  alveoli  of  the  lungs,  upon  all  the  capil- 
laries, and,  this  pressure  being  greater  than  the  capillary 
pressure,  the  entire  pulmonary  circulation  was  blocked. 
The  momentary  rise  in  the  blood-pressure  at  the  begin- 
ning of  the  drowning  was  due  to  the  fact  that  the  press- 
ure produced  by  the  water  was  greater  than  that  in  the 
capillaries ;  the  blood  in  the  pulmonary  capillaries  was 
forced  out,  and  thereby  increasing  the  quantity  of  blood 
to  the  heart  and  momentarily  raising  the  pressure.  The 
force  sufficient  to  drive  out  this  blood  was  sufficient  to 
block  the  further  flow  of  blood  in  the  capillaries,  and 
therefore  the  column  of  water  in  the  apparatus  at  such  a 
height  above  the  lungs  was  as  effective  a  block  to  the 
circulation  as  a  ligature. 

This  view  of  the  cause  of  the  collapse  of  the  circula- 
tion was  supported  by  every  necropsy  made.  In  every 
case  the  right  auricle  was  enormously  distended,  the 
right  ventricle  less  so,  while  the  left  side  of  the  heart 
was  empty.  It  is  apparent  that  the  right  side  of  the 
heart  was  unable  to  force  the  blood  in  its  chamber 
through  the  lungs  against  this  superior  resistance.  The 
necropsies  also  revealed  enormous  distention  of  all  the 
venous  trunks.  The  right  ventricle,  being  unable  to 
empty  itself,  could  not  receive  the  blood  from  the  right 
auricle,  and,  it  being  unable  to  empty  itself,  could  not 
receive  the  blood  from  the  large  venous  trunks,  and  they 


64  EXPERIMENTAL   RESEARCH   INTO  THE 

being  unable  to  empty  themselves  could  not  take  the 
blood  from  the  smaller  venous  trunks,  thus  leading  to 
their  distention.  The  arteries  were  empty  because  no 
blood  had  reached  the  left  side  of  the  heart  from  the 
lungs. 

As  to  the  respirations :  It  was  noted  in  the  protocols 
that  in  the  experiments  in  which  a  preliminary  dose  of 
atropine  had  been  given  the  respirations  were  interfered 
with  more  markedly  than  in  the  case  in  which  the  vagi 
had  been  severed.  The  same  comparison  was  made  be- 
tween the  control  experiments  and  the  "  vagal"  experi- 
ments,— namely,  that  in  the  "  vagal"  experiments  the 
respirations  were  not  so  much  interfered  with  as  in  the 
control  experiments.  This  is  interpreted  in  the  following 
manner :  The  entrance  of  water  into  the  respiratory  tract 
set  up  afferent  impulses  which  were  carried  up  to  the 
respiratory  centre  through  the  vagi ;  having  reached  the 
respiratory  centre,  afferent  impulses  were  sent  out,  causing 
interference  with  the  respirations.  Now,  in  the  cases  in 
which  the  vagi  had  been  severed,  the  afferent  impulses 
towards  the  respiratory  centre  had  been  interrupted, 
the  respiratory  centre  could  not  receive  these  afferent 
impulses,  and  for  this  reason  the  respirations  were  not 
affected. 

It  was  stated  that  the  respiratory  action  in  these  ex- 
periments was  much  less  active  than  in  cases  of  death  by 
asphyxia.  This  difference  between  the  respective  respi- 
ratory actions  is  accounted  for  as  follows :  In  the  first 
place,  what  has  just  been  stated  as  to  the  difference  be- 
tween the  respiratory  action  when  the  vagi  are  cut  and 
when  they  are  intact  tends  to  show  that  there  is  a  reflex 


HIJIUIERY    OF   TIFF.    IlKSIMIJATORY    SVSTKM  05 

inhibition  of  the  respiratory  action  in  drowning.  This, 
however,  does  not  sufficiently  account  for  the  difference 
between  the  respiratory  phenomena  in  drowning  and  in 
asphyxia,  for  in  the  experiments  in  which  the  vagi  had 
been  severed  before  the  drowning,  the  respiratory  action 
was  less  than  in  typical  cases  of  asphyxia.  The  reason 
why  this  respiratory  effort  is  less  in  this  class  of  cases  of 
drowning  than  in  asphyxia  is,  probably,  on  account  of 
the  very  great  fall  in  the  blood-pressure,  which  occurs  at 
the  onset  of  the  drowning.  That  the  respiratory  action 
is  markedly  diminished  by  a  lowering  of  the  blood-press- 
ure in  the  brain  has  been  well  established,  so  that  the 
great  collapse  in  the  blood-pressure  itself  in  these  ex- 
periments would  be  sufficient  markedly  to  diminish  the 
respiratory  action.  No  such  collapse  occurred  in  as- 
phyxia experiments.  That  the  collapse  in  the  blood- 
pressure  has  an  effect  upon  the  respiratory  action  is 
directly  shown  in  the  experiments  in  which  the  drown- 
ing pressure  was  but  slight,  producing  thereby  but  little 
fall  in  the  blood-pressure ;  in  these  cases  the  respiratory 
action  was  decidedly  greater  than  in  the  cases  in  which 
there  was  a  marked  collapse  in  the  blood-pressure. 

The  series  of  experiments  in  which  water  was  thrown 
into  the  pharynx  and  against  the  opening  of  the  larynx, 
while  the  remainder  of  the  pulmonary  tract  was  excluded, 
producing  thereby  a  marked  inhibitory  effect  upon  the 
heart  and  the  respiration,  tends  to  introduce  another  factor 
in  the  sudden  collapse  in  drowning.  If  the  foregoing  de- 
ductions are  correct,  the  circulatory  factor  in  drowning  in 
cases  in  which  the  column  of  water  exerts  its  pressure  upon 
the  pulmonary  tract  is  fully  as  potent  as  the  respiratory. 


66  EXPERIMENTAL  RESEARCH   INTO   THE 

A  RESEAUCH  INTO  THE  CAUSE  OF  CERTAIN  SYMPTOMS  OB- 
SERVED ON  ENTERING  AN  ATMOSPHERE  OF  INCREASED 
BAROMETRIC    PRESSURE 

Preliminary  Remarks. — On  entering  an  atmosphere  of 
increased  barometric  pressure  most  persons  experience 
some  peculiar  symptoms,  such  as  oppression,  dizziness, 
occasional  fainting,  difficult  breathing,  very  rapid  pulse, 
etc.  The  phenomena  observed  in  the  research  on  drown- 
ing suggested  that  some  light  might  be  thrown  upon  this 
subject  by  experiments  made  along  similar  lines. 

Protocols. — The  following  technique  was  employed  in 
the  experiments :  The  animals  were  placed  under  full 
ether  anaesthesia,  the  trachea  dissected  out,  and  a  canula 
tied  firmly  into  it ;  a  heavy  tubing  was  then  tied  upon  the 
canula,  and  this  was  connected  with  a  strong,  leather  bel- 
lows, from  which  a  large  quantity  of  air  might  be  suddenly 
or  slowly  driven  into  the  lungs, — that  is  to  say,  the  intra- 
broncho-pulmonary  pressure  might  be  increased,  as  would 
be  the  case  in  increased  barometric  pressure.  The  blood- 
pressure  was  taken  in  the  carotid  artery.  The  respira- 
tions were  neglected,  as  they  could  express  nothing  in 
such  experiments. 

1.  A  fox-terrier,  weighing  twenty  pounds,  in  good  con- 
dition, with  an  initial  blood-pressure  of  one  hundred  and 
forty-six  millimetres,  was  subjected  to  the  experiment 
outlined.  The  bellows  was  suddenly  emptied  into  the 
pulmonary  tract  of  the  dog,  producing  a  very  great  im- 
mediate fall  in  the  blood-pressure.  The  rubber  tubing 
at  the  close  of  the  injection  of  the  air  was  clamped,  the 
bellows  refilled ;  then,  as  the  air  was  again  passing  into 


SUKGERY    OF   TIIK    IIKSI'IHATOKY    SYSTEM 


CI 


the  tube,  it  was  iinclamped,  and  more  air  forced  into  the 
lungs.     In  this  manner  tiie  blood-pressure  fell  abruptly 


to   the  abscissa  line.     The  animal  was  killed  almost  in- 
stantly thereby. 

An  immediate  autopsy  showed  the  right  heart  to  be 
engorged,  the  left  heart  empty. 


68 


EXPERIMENTAL  RESEARCH   INTO   THE 


2.  A  spaniel,  weighing  twenty-four  pounds,  was  sub- 
jected to  an  experiment  similar  to  the  preceding ;  the 
blood-pressure  suffered  a  staggering  fall,  as  before.  In 
this  instance  the  pressure  fell  at  the  first  blast  almost  to 
the  abscissa  line.  On  removing  the  clip  and  allowing  the 
air  to  escape  from  the  lungs,  the  blood-pressure  leaped  up 
very  rapidly,  and  soon  regained  its  normal  height.     This 


^»ir«^   'aa^    L^    ujtd.   ^Cg&yc^ 


15.  Positive  Inflation  of  the  Lungs  increasing  the  Trachea-Pulmonary  Pressure 
BY  MEANS  OF  A  BELLOWS.— Note  the  momentary  rise  in  the  pressure,  followed  by  an  imme- 
diate staggering  fall.    The  lower  line  indicates  seconds. 

was  several  times  repeated,  so  that  there  could  be  no 
doubt  as  to  the  striking  effect  of  an  increased  intra- 
thoracic pressure  upon  the  circulation.  The  animal  was 
then  killed  by  again  increasing  the  intrathoracic  pressure, 
so  as  to  block  the  circulation  through  the  lungs. 

The  autopsy  revealed  conditions  similar  to  those  ob- 
served in  the  preceding  case. 


SURGERY   OF   TIIK    RESPIRATOIiY   SYSTEM  69 

3.  A  bull-dog,  weighing  forty  pounds,  was  subjected  to 
an  experiment  similar  to  the  preceding,  with  practically 
the  same  results.  The  animal  was  killed  almost  in- 
stantly. Observations  at  the  autopsy  were  similar  to 
the  preceding. 

4.  In  a  strong  shepherd-dog  a  control  was  made  by 
several  vigorous  blasts  from  the  bellows,  producing  col- 
lapse in  the  blood-pressure.  The  air  was  immediately 
allowed  to  escape,  and  the  blood-pressure  mounted  up 
again  to  the  point  previously  occupied.  Then,  passing 
a  scalpel  between  the  ribs  and  severing  the  descending 
vena  cava,  the  blood  gushed  in  torrents  out  of  this  vessel. 
The  blood-pressure  sank,  but  it  sank  more  gradually 
than  in  the  case  of  increased  intrapulmonary  pressure 
produced  immediately  before  by  the  injection  of  air. 

5.  A  large  St.  Bernard  was  subjected  to  the  same 
treatment  as  in  the  foregoing  case,  producing  first  the 
collapse  in  the  blood-pressure  by  forcing  air  into  the 
lungs;  then,  allowing  the  blood-pressure  to  recover  itself, 
the  inferior  vena  cava  was  severed  and  the  blood  per- 
mitted to  gush  forth  freely.  A  great  fall  in  blood-press- 
ure was  produced,  but  this  fall  was  not  so  sudden,  nor 
was  the  collapse  so  marked  as  in  the  experiment  of 
forcing  in  air. 

Summary  of  Experimental  Evidence. — The  evidence  of 
these  experiments  and  of  the  expe-riments  on  drowning 
tends  to  show  that  a  sufficient  increase  in  the  intrapulmo- 
nary pressure  may  produce  a  collapse  of  the  circulation. 
It  robs  the  left  heart  directly  of  blood,  and  therefore 
causes  a  greater  collapse  than  can  be  produced  by  sever- 
ing either  the  superior  or   the  inferior  vena  cava  alone. 


YO  EXPERIMENTAL  RESEARCH   INTO   THE 

Now,  as  a  workman  enters  a  tunnel  under  high  baro- 
metric pressure  the  respiratory  tract  is  subjected  to  an 
increase  in  pressure,  and  the  immediate  symptoms  may 
be  interpreted  from  this  main  fact.  The  dizziness,  the 
difficult  breathing,  the  soft,  rapid  pulse,  all  would  be  pro- 
duced by  a  great  fall  in  the  blood-pressure.  The  respira- 
tory symptoms  may  be  produced  by  a  sudden  fall  in  the 
blood-pressure  as  well  as  diminished  circulation  of  the 
blood,  thereby  diminishing  the  exchange  of  gas  in  the 
lungs,  which,  in  itself,  is  sufficient  to  cause  an  increased 
respiratory  action  and  produce  the  respiratory  distress. 

FOREIGN    BODIES    IN    THE    PHARYNX   AND    (ESOPHAGUS 

Preliminary  Remarks. — The  symptoms  produced  by 
foreign  bodies  of  considerable  size  lodged  in  the  pharynx 
and  certain  portions  of  the  oesophagus  bear  a  close  resem- 
blance to  those  occasioned  by  the  presence  of  foreign 
bodies  in  certain  parts  of  the  respiratory  tract. 

Among  the  symptoms  of  choking  may  be  mentioned 
cyanosis,  asphyxia,  collapse,  and  slow  pulse ;  these  symp- 
toms so  closely  resemble  those  produced  by  foreign  bodies 
in  the  larynx  that  the  one  condition  has  been  frequently 
mistaken  for  the  other,  and  in  many  cases  the  differential 
diagnosis  from  the  subjective  symptoms  alone  has  been 
quite  impossible. 

The  following  research  was  undertaken,  therefore,  to 
attempt  an  explanation  of  these  phenomena : 

Protocols. — 1.  On  a  mongrel  dog  weighing  twenty -eight 
pounds,  whose  blood-pressure  registered  one  hundred  and 
thirty-four  millimetres,  under  ether  anaesthesia,  the  follow- 
ing experiments  were  performed : 


SURGERY   OF   THE   RESPIRATORY  SYSTEM 


71 


(a)  The  oesophagus  was  exposed  by  careful  dissection, 
so  as  to  avoid  severing  any  of  the  nerves.  This  tube  was 
then  opened  by  a  longitudinal  slit  in  its  middle,  and  the 
portions  immediately  above  and  be- 
low this  slit  were  subjected  to  dila- 
tation by  means  of  a  large  bulb  and 
also  with  a  uterine  dilator.  Al- 
though the  dilatation  Avas  forcible, 
no  effect  upon  blood-pressure  was 
produced.  It  is  doubtful  whether 
the  slight  slowing  of  the  respiration 
was  a  coincidence  or  an  effect. 

{b)  Then,  passing  the  instruments 
down  to  a  point  opposite  the  bifur- 
cation of  the  trachea  and  producing 
there  a  similar  dilatation,  like  ob- 
servations were  made. 

(c)  The  instruments  were  passed 
upward  to  a  point  opposite  the 
larynx  and  dilatation  was  made ; 
there  was  a  slight  rise  in  blood- 
pressure  and  a  temporary  arrest  in 
respiration  occurred,  this  temporary 
arrest  being  followed  by  slow  respi- 
ratory efforts  during  the  remainder 
of  the  dilatation. 

(c?)  The  same  experiment  was  repeated  with  similar  re- 
sults. Then,  passing  the  dilator  down  to  the  cardiac  ori- 
fice of  the  oesophagus  and  dilating  this  tube,  there  was 
produced  a  slight  fall  of  blood-pressure,  and  the  respira- 
tions were  diminished  in  frequency. 


16.  Experiment  ox  Choking, 
by  pressing  a  globular  for- 
EIGN Body  into  the  (Esopha- 
gus OPPOSITE  the  Larynx.— 
Note  the  temporary  inhibition 
of  the  respiration  (upper 
tracing)  and  the  staggering 
fall  in  the  blood-pressure 
(second  tracing). 


72  EXPERIMENTAL   RESEARCH   INTO  THE 

(e)  Introducing  from  below  upward  the  rounded  handle 
of  an  instrument  larger  than  the  opening  into  the  pharynx, 
producing  thereby  as  great  a  dilatation  as  possible  of  the 
upper  portion  of  the  oesophagus,  there  followed  a  very 
marked  fall  in  blood-pressure,  and  the  character  of  the 
heart-beats  displayed  the  distinct  effect  of  "  vagal"  action. 
The  respirations  at  the  same  time  were  very  much  slowed. 
The  middle  portion  of  the  oesophagus  was  then  again 
dilated  with  as  much  force  as  possible,  resulting  in  a 
slight  irregularity  of  respiration  with  an  unchanged 
blood-pressure  curve. 

(/)  Forcible  dilatation  of  the  oesophagus  again  upon  a 
level  with  the  upper  portion  of  the  larynx  and  at  the  end 
of  the  pharynx  produced  a  very  great  immediate  fall  of 
the  blood-pressure  and  complete  arrest  of  respiration. 
The  narrowest  portions  of  the  oesophageal  tube  were  at 
the  pharyngeal  and  the  cardiac  extremities. 

2.  On  a  mongrel  dog,  in  poor  condition,  weighing 
twenty-three  pounds,  under  ether  anaesthesia,  the  follow- 
ing experiments  were  performed : 

{a)  Introduction  of  the  rounded,  wooden  handle  of  an 
instrument  into  the  pharynx  produced  a  marked  "  vagal" 
cardiac  action  and  irregular,  slowed  respirations.  This  was 
twice  repeated,  with  the  same  result  each  time.  The  mid- 
dle portion  of  the  oesophagus  was  again  dilated,  and  it  was 
found  that  but  minor  effects  were  produced  from  as  little 
or  as  much  dilatation  as  was  possible  of  this  tube  from 
the  lower  level  of  the  larynx  down  to  near  the  cardiac 
orifice. 

(b)  On  forcing  an  obturator  into  the  oesophagus  very 
slowly  upward  until  it  entered  the  cavity  of  the  mouth, 


SURGERY   OF   'VWK    l{, ASPIRATOR Y   SYSTEM  73 

no  appreciable  effects  wore  produced  until  it  reached  a 
point  opposite  the  upper  half  of  the  larynx,  when  a 
marked  fall  in  the  blood-pressure  occurred  and  temporary 
respiratory  arrest. 

(c)  An  injection  of  atropine,  in  sufficient  dose  (as  proven 
by  the  DuBois-Reymond  stimulation)  to  paralyze  the 
nerve-endings  of  the  vagi,  was  given.  Then,  on  repeat- 
ing the  dilatation  or  choking  in  the  area  opposite  the 
upper  portion  of  the  larynx  and  in  the  pharynx,  no 
effect  upon  the  blood-pressure  was  observed  ;  the  respira- 
tions were  arrested  as  before. 

3.  On  a  Newfoundland  dog  weighing  forty  pounds,  in 
good  condition,  with  a  blood-pressure  of  one  hundred  and 
twenty-eight  millimetres,  under  ether  anaesthesia,  the 
following  experiments  were  performed  : 

(a)  The  rounded  wooden  end  of  an  instrument,  larger 
than  the  normal  opening  of  the  pharynx,  was  rather 
forcibly  pressed  through  the  mouth  into  the  pharynx. 
This  produced  an  immediate  and  very  considerable  fall  in 
blood-pressure  with  temporary  arrest  of  respiration,  fol- 
lowed by  irregular,  slow,  respiratory  efforts.  Introducing 
the  same  into  the  cardiac  end  of  the  oesophagus  through 
an  incision  in  the  stomach,  there  was  a  slight  fall  in 
blood-pressure  and  slightly  irregular  respirations.  Then, 
by  exposing  the  oesophagus  in  the  middle  of  the  neck  and 
making  a  longitudinal  opening,  the  instrument  was  passed 
through  this  incision  upward,  forcibly  dilating  at  a  point 
opposite  the  larynx,  Avhereupon  there  was  an  immediate 
and  very  considerable  fall  in  blood-pressure,  with  tempo- 
rary arrest  of  the  heart  and  of  respiration. 

{b)  A  physiologic  dose  of  atropine  was  given,  and  its 


74  EXPERIMENTAL   RESEARCH   INTO   THE 

efl&ciency  proved  in  the  usual  way.  Then  a  repetition  of 
the  foregoing  experiment  produced  but  little  effect  upon 
the  blood-pressure,  the  little  being  sometimes  a  rise,  some- 
times a  fall ;  but  it  did  not  prevent  the  arrest  of  respira- 
tion. 

4.  On  a  bull-dog  in  good  condition,  weighing  twenty- 
eight  pounds,  having  a  blood-pressure  of  one  hundred 
and  forty-five  millimetres,  under  ether  anaesthesia,  the 
following  experiments  were  performed  : 

{a)  Forcible  dilatation  of  the  oesophagus  in  its  middle 
portion  produced  a  rise  in  blood-pressure  and  a  slight 
slowing  of  respiration.  This  was  repeated  twice,  in  dif- 
ferent portions  of  the  oesophagus,  with  like  results. 

{b)  The  same  experiment  opposite  the  upper  portion  of 
the  larynx  produced  a  marked  fall  in  blood-pressure,  with 
"  vagal"  beats  and  temporary  arrest  of  respiration  ;  later 
on  the  respirations  recovered  their  normal  rhythm. 

(c)  A  physiologic  dose  of  atropine,  proved  in  the 
usual  way,  prevented  the  effect  upon  the  heart,  as  was 
shown  in  the  preceding  case,  but  the  respirations  were 
arrested  again,  as  before.  Now,  making  sections  of  both 
superior  laryngeal  nerves  and  repeating  the  experiment 
of  choking  opposite  the  larynx,  there  was  no  effect  pro- 
duced upon  either  the  cardiac  or  the  respiratory  action. 

Traction  downward  upon  the  oesophagus  produced  a 
fall  in  the  blood-pressure,  but  the  characteristic  "  vagal" 
beats  were  not  observed  and  the  respirations  were  unal- 
tered. Traction  upward  produced  a  slight  rise  in  blood- 
pressure,  with  no  alteration  in  respiration. 

5.  On  a  mongrel  dog  weighing  twenty  pounds,  blood- 
pressure  one  hundred  and  forty-eight  millimetres,  in  good 


SURGERY   OF  THE   RESPIRATORY   SYSTEM  75 

health,  under   chloroform  anaesthesia,  the  following  ex- 
periments were  performed : 

(a)  The  handle  of  a  chisel  passed  into  the  pharynx 
and  forced  down  in  imitation  of  choking  produced  a 
marked  fall  in  the  blood-pressure  and  arrest  of  respira- 
tion. The  pressure  of  the  chisel  did  not  come  in  contact 
with  the  larynx,  but  with  the  pharynx  and  the  base  of 
the  tongue. 

(b)  A  physiologic  dose  of  atropine  prevented  the  ap- 
pearance of  the  blood-pressure  phenomena  on  repetition 
of  the  experiments.  The  respirations  were  arrested  as 
before.  Various  portions  of  the  oesophagus  were  then 
tested,  and  with  the  exception  of  the  cardiac  end,  there 
was  but  little  effect  upon  either  the  respiration  or  the 
blood-pressure.  The  cardiac  end  was  finally  dilated  with 
a  Goodell  dilator  with  very  great  force,  the  operation 
resulting  in  a  slight  slowing  of  respiration.  Finally,  on 
severing  both  superior  laryngeal  nerves,  then  repeating 
the  pharyngeal  choking  experihient,  there  was  a  rise 
produced  in  blood-pressure  instead  of  a  fall,  and  the 
respirations  remained  undisturbed.  Downward  traction 
with  considerable  force  upon  the  oesophagus  produced 
a  fall  in  blood-pressure  with  slight  respiratory  slowing ; 
upward  traction  produced  a  much  less  fall  in  blood- 
pressure  and  no  respiratory  alteration. 

6.  On  a  bird-dog  weighing  thirty-two  and  one-half 
pounds,  with  blood-pressure  of  ninety  millimetres,  in  good 
condition,  under  chloroform  anaesthesia,  the  following 
experiments  were  performed : 

(a)  The  wooden  handle  of  an  instrument  was  placed 
deep  in  the  pharynx,  and  the  free  end  carried  outward 


76  EXPERIMENTAL   RESEARCH   INTO  THE 

into  the  angle  of  the  mouth,  so  as  to  produce  a  severe 
prying  pressure  against  the  walls  of  the  pharynx.  This 
produced  a  staggering  fall  in  the  blood-pressure,  with 
complete  temporary  arrest  of  the  heart  and  of  the  respira- 
tion. On  severing  both  superior  laryngeal  nerves  and  re- 
peating the  experiment  there  was  a  very  marked  fall  in 
the  blood-pressure,  with  temporary  arrest  of  the  heart  as 
before,  but  the  respirations  remained  unaltered. 

{b)  Division  of  the  hypoglossal  nerves  on  both  sides 
and  repeating  the  experiment  produced  a  temporary  arrest 
of  the  heart,  with  a  staggering  fall  of  the  blood-pressure, 
but  no  effect  upon  the  respiration. 

(c)  As  a  control,  very  severe  intralaryngeal  manipula- 
tion was  made,  which  produced  no  effect  upon  either  the 
respiration  or  the  heart's  action.  Then  choking  was  again 
done  in  the  same  violent  way,  through  the  mouth  with  the 
wooden  handle  of  an  instrument,  producing  thereby  the 
same  inhibition  of  the  heart  as  before. 

7.  On  a  thirty-nine-pound  dog,  with  blood-pressure 
at  one  hundred  and  ten  millimetres,  in  poor  condition, 
under  chloroform  anaesthesia,  the  following  experiments 
were  performed :  The  glossopharyngeal,  the  hypoglossal, 
and  the  superior  laryngeal  nerves  on  each  side  were  ex- 
posed, looped  with  thread,  and  the  animal  prepared  for 
the  following  tests : 

{a)  As  a  control,  the  animal  was  choked  from  below 
upward,  opposite  the  upper  portion  of  the  larynx,  with 
the  production  of  the  usual  inhibitory  phenomena ;  then, 
through  the  mouth  with  the  usual  force,  pharyngeal 
choking  was  practised,  and  resulted  in  the  usual  inhibi- 
tory phenomena. 


SURGERY   OF   THE   JlESIMIlATOIiV    SYSTEM  77 

{b)  Now  both  glossopharyngeal  nerves  were  severed. 
Then,  on  repeating  the  above  control  manipulations,  like 
inhibitory  phenomena  were  produced. 

(c)  Division  of  both  hypoglossal  nerves  and  then  re- 
peating the  choking  experiments  produced  practically  the 
same  reflex  phenomena  upon  both  respiration  and  the 
heart. 

(d)  An  injection  of  one-one-hundredth  of  a  grain  of 
atropine  into  the  jugular  vein.  Repetition  of  the  same 
experiments  j)roduced  no  effect  upon  either  the  respira- 
tion or  the  heart's  action.  In  the  experiment  of  choking, 
especially  when  the  foreign  body  was  large,  there  was 
evidence  that  the  vagus  itself  was  mechanically  stimu- 
lated, either  directly  by  a  direct  continuity  of  pressure, 
or  indirectly  by  being  dragged  on  by  structures  that  had 
a  connecting  anatomical  relation  with  it,  and  that  thereby 
a  direct  inhibition  was  produced. 

Summary  of  Experimental  Evidence. — It  is  noted  in  all 
the  cases  that  the  narrowest  portions  of  the  pharyngo- 
oesophageal  tract  were  at  the  pharyngeal  and  the  gastric 
ends  of  the  tube  respectively.  Artificial  choking  pro- 
duced at  the  gastric  end  of  the  oesophagus  had  some  effect 
upon  the  respiration,  usually  slowing  it,  and  caused,  also, 
some  fall  in  the  blood-pressure,  but  in  no  case  were  the 
effects  of  a  striking  nature.  They  were  properly  classed  as 
minor  phenomena.  In  no  exjjerinaent  on  any  part  of  the 
oesophageal  tract  up  to  a  point  opposite  the  larynx  were 
more  than  minor  effects  produced.  Severe  dilatation  of 
this  portion  of  the  tube  sometimes  produced  a  rise,  some- 
times a  fall,  in  the  blood-jDressure ;  the  respiratory  effects 
were  never  of  much  importance.     However,  at  the  points 


78  EXPERIMENTAL  RESEARCH   INTO   THE 

opposite  the  larynx,  especially  the  upper  portion  of  the 
larynx,  very  marked  respiratory  and  circulatory  phenom- 
ena were  caused  by  artificial  choking.  These  effects  were 
doubtless  inhibitory  and  through  the  vagus. 

That  the  cardiac  action  was  through  the  vagus  is  proved 
by  the  fact  that  physiologic  dosage  of  atropine  in  every 
case  prevented  the  fall  in  blood-pressure  and  the  "  vagal" 
strokes.  That  the  superior  laryngeal  nerve  was  not  the 
only  path  over  which  the  inhibiting  impulses  passed  is 
proved  by  the  fact  that  the  pharyngeal  choking,  espe- 
cially when  accompanied  by  considerable  violence,  pro- 
duced a  marked  fall — in  fact,  a  collapse — in  blood-press- 
ure after  the  superior  laryngeal  had  been  severed.  That 
it  was  not  through  the  hypoglossal  or  the  glossopharyn- 
geal that  this  collapse  was  produced  was  proved  by  the 
observation  that  the  same  phenomena  occurred  after  their 
severance. 

Direct  observation  of  the  mechanic  dragging  upon  the 
upper  portion  of  the  vagus  through  the  medium  of  the 
numerous  anatomic  structures  lying  in  such  close  appo- 
sition to  it  and  so  closely  interwoven,  together  with  the 
negative  proof  adduced  by  the  experiments,  was  sufiicient 
to  show  that  a  part  at  least  of  the  inhibition  phenomena 
were  due  to  a  mechanic  stimulation  of  the  vagus  itself. 
It  is  highly  probable  that  the  marked  respiratory  arrest 
was  due  to  a  mechanic  irritation  of  the  superior  laryn- 
geal ;  but  that  it  was  not  the  only  tract  over  which  im- 
pulses passed  was  proved  by  a  slight  alteration  in  the 
respiratory  action  after  the  superior  laryngeal  had  been 
severed,  although  no  such  marked  effects  as  before  could 
be  produced.     It  is  true,  however,  that  all  the  evidence 


SUllGiEllY    OF   THE   liESlMllATORY    SYSTEM  79 

goes  to  show  that  the  superior  laryngeal  is  the  only  source 
through  which  choking  may  cause  very  striking  reflex 
inhibition  of  the  respiration.  Tolerance,  so  far  as  the 
respirations  are  concerned,  is  very  soon  acquired ;  it  is 
later  acquired  on  the  part  of  the  circulation. 

Some  Observations. — Choking,  then,  produced  symp- 
toms of  reflex  inhibition,  partly  through  the  superior 
laryngeal,  and  partly  through  the  trunk  of  the  vagus 
itself,  symptoms  almost  identical  with  those  of  severe  irri- 
tation of  the  larynx  itself.  In  the  case  of  the  larynx  all 
the  symptoms  are  due  to  mechanic  stimulation  of  the 
superior  laryngeal  nerves.  In  a  given  case,  then,  of 
threatened  asphyxia,  if  operative  procedures  are  to  be 
undertaken  for  dislodgement  of  a  foreign  body,  it  would 
be  well  to  be  guided  by  the  same  principles  that  guided 
in  the  treatment  of  foreign  bodies  in  the  larynx,  at  least 
so  far  as  to  give  the  preliminary  dosage  of  atropine  to 
prevent  a  great  collapse  or  possible  death  during  the 
operative  procedures.  It  is  perfectly  apparent  that  in 
case  there  is  a  history  of  choking  without  inhibition 
phenomena,  the  foreign  body,  if  large  enough  to  cause 
much  pressure,  must  be  at  a  point  below  the  level  of 
the  larynx. 

FOREIGN    BODIES    IN    THE   TRACHEA    AND    THE    LARYNX 

Preliminary  Remarks. — In  cases  of  foreign  bodies  in 
the  respiratory  tract  there  is  often  from  the  symptoms 
alone  great  difficulty  in  determining  their  location.  It  is 
difficult  also  to  decide  whether  or  not  an  operation  is 
indicated,  and,  if  indicated,  where  this  operation  is  to  be 
performed.     The  number  of   futile  attempts   at  finding 


80  EXPERIMENTAL   RESEARCH   INTO   THE 

foreign  bodies,  and  the  number  of  catastrophes  that 
have  followed  such  accidents,  suggested  the  following 
research. 

Protocols. — The  following  experiments  were  made  with 
a  view  to  ascertaining  the  comparative  values  of  chloro- 
form and  ether  in  point  of  safety  in  operations  involving 
the  upper  air-passages : 

1.  On  a  sixteen-pound  mongrel,  in  fair  condition, 
under  ether  anaesthesia,  the  following  dissections  were 
made :  Both  vagi  were  dissected  free  from  the  carotids 
throughout  the  length  of  the  neck ;  then  the  superior 
laryngeals  were  dissected  out  from  their  origin  in  the 
vagi  to  their  entrance  into  the  box  of  the  larynx ;  next 
the  glossopharyngeal  was  dissected  out  from  its  exit  from 
the  cranial  cavity  to  its  terminals  in  the  muscles  ;  finally, 
the  hypoglossal  was  similarly  dissected,  thus  exposing 
these  structures  on  both  sides.  During  the  dissections 
the  animal  breathed  fairly  well  without  requiring  much 
attention  to  the  ether  anaesthesia,  which  was  administered 
by  means  of  a  tracheal  tube,  to  which  a  rubber  tube  and 
funnel  were  attached,  and  into  the  latter  cotton-wool  was 
thrust.  Manipulations  of  these  nerves,  especially  of  the 
vagus  and  inferior  laryngeal,  interfered  with  the  respira- 
tory action  as  well  as  the  circulatory.  However,  in  no 
instance  was  it  necessary  to  supply  artificial  respiration. 

2.  On  a  seventeen-pound  bird-dog,  under  chloroform 
anaesthesia,  dissections  were  carried  out  as  nearly  like  the 
preceding  as  possible,  occupying  as  nearly  as  possible  the 
same  length  of  time  in  their  performance.  During  the 
anaesthesia  it  was  noted  that  the  blood-pressure  would 
sink  whenever  the  respirations  became  slowed,  and  that 


SURGERY   OF   THE   RESPIRATORY   SYSTEM 


81 


the  pressure  would  recover  itself  upon  removal  of  the 
anaesthetic.  Early  in  the  experiment  it  was  found  neces- 
sary to  maintain  artificial  respiration  for  a  short  period 
of  time,  and  during  the  latter  part  of  the  dissection  res- 
pirations became  extremely  shallow  and  weak.  Manip- 
ulation of  the  superior  laryngeal 
or  the  vagus  interfered  with  the 
resi^irations  more  markedly  than 
in  the  preceding  experiment. 

3.  On  a  water-spaniel  weighing 
twenty-four  pounds  and  in  good 
condition,  under  ether  anaesthesia, 
the  following  experiment  was  per- 
formed :  The  trachea  and  the  lar- 
ynx were  both  dissected  free,  the 
trachea  severed  at  the  cricoid 
junction,  then  the  superior  laryn- 
geal was  dissected  out  from  its 
origin  to  its  termination  on  both 
sides  of  the  neck.  A  finger  was 
passed  up  within  the  larynx,  pro- 
ducing thereby  an  irritation  in  the 
area  for  inhibition.  The  superior 
laryngeals  were  stimulated  by  the 
faradic  current,  producing  tem- 
porary arrest  of  respiration  and 
complete  inhibition  of  the  heart, 
stimulation  both  the  cardiac  and  the  respiratory  action 
were  resumed.  After  this  the  animal  was  allowed  to  rest 
undisturbed  with  these  structures  exposed  to  the  air.  The 
respirations  were  decreased  in  am})litude  and  in  frequency, 


17.  Experiment  on  the  Re- 
moval OF  A  Laryngeal  Tube  by 
MEANS  OF  External  Manipula- 
tion.— The  upper  tracing  repre- 
sents the  respiration,  the  next 
the  blood-pressure,  below  which 
are  the  signal  and  the  time. 


On  cessation  of  the 


82  EXPERIMENTAL  RESEARCH   INTO  THE 

but  at  no  time  ceased,  excepting  when  some  special  irri- 
tation produced  reflex  inhibition. 

4.  A  bull-terrier,  weighing  twenty-eight  pounds,  in 
fair  condition,  under  chloroform  anaesthesia,  was  subjected 
to  as  nearly  as  possible  the  same  procedures  as  in  the 
foregoing  case,  occupying  about  the  same  length  of  time, 
with  the  following  result :  The  reflex  inhibitions  on  both 
the  respiration  and  the  heart  were  under  chloroform  an- 
aesthesia comparatively  more  profound.  During  the  dis- 
section respirations  were  so  shallow  as  to  cause  consider- 
able cyanosis,  and  for  a  time  artificial  respirations  were 
supplied.  At  the  close  of  the  experiment,  when  the  ani- 
mal was  allowed  to  rest,  the  respiratory  action  was  ex- 
tremely feeble  and  the  blood-pressure  had  fallen  more 
than  one-half  from  its  original  height. 

5.  On  a  mongrel  cur,  weighing  eighteen  pounds,  under 
ether  anaesthesia,  the  following  experiments  were  per- 
formed :  The  superior  laryngeal  nerves  on  both  sides 
were  exposed  and  subjected  to  stimulation  by  mechanical 
manipulation,  producing  thereby  a  reflex  arrest  of  respi- 
ration. The  faradic  current  was  then  applied,  producing 
reflex  inhibition  of  both  the  respiratory  and  the  cardiac 
action.  This  was  repeated  twice  on  each  side.  The 
normal  action  was  regained  with  a  fair  degree  of  readi- 
ness after  cessation  of  the  stimulation  in  each  instance. 
Artificial  respirations  w^ere  not  required. 

6.  On  a  water-spaniel  weighing  twenty-two  pounds,  in 
fair  condition,  under  chloroform  anaesthesia,  during  the 
technique  of  dissecting  out  the  trachea  and  applying  the 
tracheal  apparatus  for  maintaining  anaesthesia,  respira- 
tions ceased  and  artificial  respiration  was  supplied  during 


SURGERY   OP  THE   RESPIRATORY   SYSTEM  83 

a  period  of  five  minutes,  after  which  very  slow,  voJuiitary 
efforts  were  noted,  gradually  increasing  in  amplitude  and 
rapidity  until  an  over-respiratory  action  and  recovery 
occurred.  On  reducing  the  animal  to  surgical  anaesthesia 
again,  a  like  result  was  observed.  During  the  experi- 
ment, carried  out  as  nearly  as  possible  as  in  the  preceding 
case,  the  respirations  were  very  much  slowed  and  quite 
shallow,  so  that  it  was  difficult  to  obtain  a  good  tracing. 
In  these  experiments  the  larynx  was  exposed  to  all  kinds 
of  rude  manipulation,  for  the  purpose  of  facilitating  a 
comparison  between  the  results  under  chloroform  and 
under  ether  anaesthesia. 

7.  This  experiment  and  the  following  were  performed 
for  the  purpose  of  determining  whether  or  not  traction 
on  the  trachea  from  the  lungs  upward,  or  from  the  larynx 
downward,  or  lifting  the  entire  trachea  forcibly  out  of 
its  bed,  caused  an  effect  upon  the  blood-pressure  and  the 
respiration. 

On  a  mongrel  dog  weighing  twenty  pounds,  under 
ether  anaesthesia,  the  following  experiment  was  per- 
formed :  The  trachea  was  freely  exposed  by  bloodless 
dissection,  and  after  securing  a  control  tracing  of  the 
respiration  and  the  blood-pressure,  a  hook  was  placed 
between  the  rings  of  the  upper  portion  of  the  trachea 
and  the  latter  organ  was  pulled  strongly  upward  from 
the  lungs  in  the  line  of  its  own  axis.  *  This  produced  no 
effect  upon  the  respiratory  rhythm,  but  it  caused  a  fall 
in  blood-pressure,  this  fall  taking  the  form  of  a  rather 
sharply  rounded  curve,  from  which  it  quickly  recovered. 
Then,  repeating  the  same  manoeuvre,  like  effects  were 
produced.     The  line  of  traction  was  then  reversed  and 


84 


EXPERIMENTAL   RESEARCH   INTO   THE 


the  trachea  dragged  downward  on  the  line  of  its  own 
axis,  producing  a  dragging  uiDon  the  entire  larynx  and 
the  pharynx.  This  was  followed  by  a  decided  fall  in 
the  blood-pressure  and  a  temporary  slowing  of  respira- 
tion.    This   experiment  was   twice   repeated,   with    like 

results,  though  in  each  sub- 
sequent repetition  the  phe- 
nomena were  not  so  marked 
as  in  the  one  immediately 
preceding.  In  dragging  up- 
ward on  the  trachea,  when 
the  dragging  was  quickly 
applied,  the  fall  in  blood- 
pressure  was  correspondingly 
more  abrupt,  and  suggested 
the  probable  action  of  me- 
chanical causes  interfering 
with  the  return  circulation  in 
the  venous  trunks  which  pass 
in  such  close  anatomical  rela- 
tion to  the  trachea. 

8.  The  animal,  a  fox-ter- 
rier, weighing  twenty  pounds, 
was  subjected  to  experiments 
similar  to  those  in  the  pre- 
ceding case.  The  phenomena  attending  upward  traction 
on  the  trachea  were  practically  the  same  as  in  the  pre- 
ceding case,  except  that  there  seemed  to  be  some  increase 
in  the  depth  of  respirations.  On  dragging  down  on  the 
trachea  the  respirations  were  more  decidedly  slowed,  and 
for  a  short  period  at  the  first  dragging,  respirations  were 


18.  Experiment  on  the  Trachea. — 
The  upper  tracing  represents  respiration, 
the  next  the  hlood-pressure,  and  the 
lower  two  the  signal  and  the  time  (in 
seconds). 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  85 

arrested.  On  raising  the  trachea  up  out  of  its  bed  with 
some  force,  results  similar  to  dragging  down  upon  the 
trachea  were  produced. 

9.  On  a  bull-dog  weighing  forty  pounds,  under  ether 
anaesthesia,  experiments  similar  to  the  preceding  were 
performed,  with  the  same  results,  except  that  in  dragging 
forcibly  down  upon  the  trachea  there  was  a  distinct  in- 
hibitory action  upon  the  heart,  whereby  sweeping  slow 
beats  were  executed  during  the  period  of  most  forcible 
traction.  Kaising  the  trachea  up  from  its  bed  with  con- 
siderable force  produced  similar  symptoms,  though  less 
marked. 

While  the  first  six  experiments  involved  the  mere  dis- 
section and  thorough  stimulation  of  certain  nerves,  they 
confirm  what  has  been  very  frequently  observed  in  other 
experiments  upon  the  respiratory  tract, — viz.,  that  ani- 
mals under  chloroform  ansesthesia  are  decidedly  more 
liable  to  respiratory  failure  than  animals  under  ether 
anaesthesia.  While  it  is  recognized  that  it  is  very  diffi- 
cult to  make  satisfactory  comparative  observations,  it  has 
seemed  that  reflex  inhibitory  phenomena  are  more  pro- 
found under  chloroform  anaesthesia  than  under  ether 
anaesthesia,  inasmuch  as  in  other  experimental  work,  not 
relating  to  this  present  object  and  purpose,  similar  obser- 
vations have  been  made.  These  additional  experiments 
have  been  made  principally  to  test  .the  effect  of  dissec- 
tions upon,  and  about  the  larynx  and  trachea,  and  involving 
the  nerve-trunks  supplying  this  area. 

The  Physiologic  Principles  involved. — The  physiologic 
principles  involved  in  this  question  are  practically  the 
same  as  those  indicated  under  several  other  headings  in 


86  EXPERIMENTAL  RESEARCH   INTO   THE 

this  paper, — namely,  that  no  amount  of  irritation  of  the 
mucosa  or  structure  of  the  trachea,  even  the  cricoid  por- 
tion of  the  larynx,  is  capable  of  producing  any  marked 
sudden  effects  upon  either  the  circulation  or  the  respira- 
tion. 

Such  an  irritation,  however,  if  applied  to  the  middle 
or  upper  portion  of  the  larynx,  would  cause  most  pro- 
nounced reflex  inhibitory  phenomena.  The  only  reflex 
phenomenon  a  foreign  body  below  the  larynx  could  pro- 
duce is  that  of  coughing.  While  in  the  larynx  not  only 
coughing  may  be  produced  on  slight  irritation,  but,  on  a 
greater  irritation,  reflex  arrest  of  respiration  will  occur, 
and  on  a  still  greater  irritation,  in  addition  to  the  reflex 
arrest  of  respiration,  there  may  be  reflex  arrest  of  the 
heart's  action,  causing  thereby  a  collapse  more  or  less 
profound.  The  symptoms  of  asphyxia  from  obstruction 
need  never  be  mistaken  for  those  of  reflex  inhibition 
from  the  laryngeal  area. 

In  the  case  of  asphyxia  from  obstruction,  the  respira- 
tory, as  well  as  the  circulatory,  activity  will  continue. 
The  pulse  will  be  strong  and  full,  and  slow,  until  finally, 
after  five  to  eight  minutes,  there  will  be  intermissions, 
then  irregular  actions,  then  intermissions,  until  finally 
the  heart  ceases  in  diastole.  In  reflex  inhibition  there  is 
sudden  collapse,  with  sudden  cessation  of  respiratory 
action,  and,  if  the  circulatory  action  is  also  affected,  there 
will  be  no  arrest  of  the  heart  as  sudden  as  the  arrest  of 
the  respiration. 

Differential  Diagnosis  between  Lodgement  in  the  Trachea 
and  in  the  Larynx. — A  foreign  body  lodging  in  the  trachea 
and  not  dislodged  from  the  trachea  during  the  attacks  of 


SURGERY   OF  THE   RESPIRATORY   SYSTEM  87 

coughing,  is  incapable  of  producing  any  effect  other  than 
that  indirectly  produced  by  the  powerful  respiratory 
alterations  in  the  act  of  coughing.  If  the  foreign  body 
is  so  large  and  the  swelling  so  great  as  to  completely 
obstruct  the  tube,  the  symptoms  of  asphyxia,  as  above 
described,  will  appear.  If,  however,  the  foreign  body  is 
lodged  in  the  larynx,  there  are  likely  to  appear  attacks 
of  cyanosis,  sudden  in  onset,  during  which  the  subject 
becomes  cyanotic,  greatly  depressed, — in  short,  passes 
into  collapse, — and,  after  a  variable  period,  respirations 
gradually  are  resumed,  the  cyanosis  disappears,  and  the 
heart  again  beats  normally  for  that  particular  case. 

A  slight  movement,  or  a  cough,  or  an  attempt  at  exam- 
ination, may  precipitate  such  a  collapse.  Furthermore, 
supposing  a  foreign  body  to  have  been  inspired  into  the 
trachea  and  during  a  violent  fit  of  coughing  to  have  been 
expelled  from  the  trachea  into  the  larynx,  such  reflex  in- 
hibition would  most  likely  suddenly  appear.  If,  then,  a 
sudden  collapse  takes  its  onset  in  the  middle  or  the  latter 
part  of  a  severe  coughing  spell,  it  may  be  assumed  that 
that  foreign  body  had  not  been  in  the  larynx  at  the 
beginning  of  the  coughing,  but  it  was  forced  into  the 
larynx  by  the  powerful  expiratory  efforts. 

Preliminary  Preparation  for  Extraction  of  the  Foreign 
Body. — In  all  cases  of  operative  procedure  to  extract 
foreign  bodies  from  the  respiratory  tract  it  would  seem 
a  judicious  precaution  to  inject  a  sufficient  dosage  of 
atropine  to  protect  the  heart  against  the  reflex  inhibitory 
impulses  through  the  superior  laryngeal  nerve,  so  that, 
if  respirations  should  fail,  the  circulation  will  be  suf- 
ficiently guarded,  so  that,  while  artificial  respirations  are 


88  EXPERIMENTAL   RESEARCH   INTO   THE 

maintained,  the  operation  may  be  completed.  This  is 
especially  necessary  in  cases  in  which  the  diagnosis  has 
been  made  of  lodgement  in  the  larynx. 

However,  in  cases  not  so  diagnosticated,  there  is  by  no 
means  a  certainty  that  in  the  fits  of  coughing  the  foreign 
body  will  not  be  forced  into  that  organ  before  the  tech- 
nique can  be  completed.  In  cases  in  which  it  is  practica- 
ble, a  spray  of  cocaine  or  an  intralaryngeal  application  of 
cocaine  are  of  the  greatest  service  in  protecting  the  patient 
against  sudden  collapse.  As  has  been  amply  proved,  ex- 
perimentally as  well  as  clinically,  the  local  application  of 
cocaine  upon  the  laryngeal  mucosa,  even  with  so  weak  a 
solution  as  one-half  per  cent.,  completely  prevents  the 
reflex  inhibitory  effect  upon  both  the  respiration  and  the 
heart,  no  matter  to  what  extent  the  irritation  of  the  larynx 
may  be  carried.  In  cases  in  which  this  preliminary  prep- 
aration can  be  satisfactorily  carried  out,  it  would  give  an 
absolutely  certain  precaution  against  sudden  collapse  or 
death. 

On  the  Technique  of  the  Operative  Procedure. — In  every 
case  in  which  it  is  possible,  local  rather  than  general  an- 
aesthesia should  be  employed.  The  principal  reasons  for 
this  preference  are  the  following :  If  the  subject  can  be 
controlled  so  that  the  operation  may  be  performed  under 
local  anaesthesia,  there  is  less  disturbance,  less  struggle, 
and  therefore  less  opportunity  for  dislodging  the  foreign 
body  ;  the  patient  may  aid  the  surgeon  in  various  ways 
in  his  attempt  to  recover  the  foreign  body  ;  and  finally, 
when  the  respiratory  passages  are  so  occluded  as  to  re- 
quire the  action  of  extraordinary  muscles  of  respira- 
tion it  would  be  almost  fatal  to  attempt  a  general  anses- 


SURGERY   OF   THE   RKSIMRATORY    SYSTKM  H9 

thetic,  because  in  this  case  the  exchange  of  air  can  only 
be  accomplished  by  the  aid  of  the  extraordinary  muscles. 
Now,  a  general  anaesthetic  paralyzes  these  extraordinary 
muscles  of  respiration,  and  therefore  the  burden  of  sup- 
plying air  is  thrown  upon  the  ordinary  muscles  of  respi- 
ration, which  are  incapable  of  performing  this  function, 
and  the  patient  necessarily  dies  of  suffocation.  The  im- 
portance of  recognizing  these  two  factors  in  labored  re- 
spiratory action,  in  view  of  the  fact  that  one  group  of 
muscles  is  paralyzed  by  general  anaesthesia,  cannot  be 
over-estimated. 

In  the  choice  of  local  anaesthesia  cocaine  is  preferable 
to  eucaine.  The  reasons  for  this  preference  are  the  fol- 
lowing :  Cocaine  produces  ischaemia,  while  eucaine  pro- 
duces hyperaemia.  Inasmuch  as  hemorrhage,  even  slight, 
is  of  considerable  significance  in  this  operation,  cocaine  to 
that  extent  is  preferable.  The  effect  of  cocaine  is  more 
prompt  than  that  of  eucaine,  and,  inasmuch  as  in  this 
operation  expedition  is  so  often  urgently  demanded,  the 
operation  may  be  more  quickly  performed  under  the  more 
quickly  acting  anaesthetic.  And  finally,  the  necessary 
dosage  of  either,  when  properly  used,  is  insufficient  to 
endanger  life. 

A  one-tenth  per  cent,  solution  has  been  found  of  suffi- 
cient strength  in  my  experience  for  inducing  anaesthesia. 
It  might  be  well  to  point  out  here  that  after  the  skin  in- 
cision has  been  made,  but  few  sensory  nerve- terminals  will 
be  encountered  in  the  section  through  the  subcutaneous 
tissue  until  the  structure  of  the  trachea  or  the  larynx 
has  been  reached.  It  is  necessary  to  pause  here  and  inject 
a  new  line  of  the  anaesthetic.    It  is  sometimes  unnecessary 


90  EXPERIMENTAL   RESEARCH   INTO   THE 

to  inject  any  ansesthetic  in  the  dissection  between  the  skin 
and  the  surface  of  the  respiratory  tube.  After  making 
the  incision  into  the  respiratory  tube  it  is  advisable  to 
apply  cocaine  or  eucaine  upon  the  mucosa  by  means  of  a 
swab  or  spray  for  some  distance  above  and  below  the 
opening,  at  least  a  distance  sufficient  to  protect  the  area 
of  possible  operative  procedures. 

It  is  especially  important,  if  the  larynx  can  be  reached 
from  the  point  of  opening,  to  cocainize  its  interior.  This 
having  been  done,  sudden  collapse  and  death  are  quite 
impossible.  This  statement  may  seem  rather  positive,  but 
any  one  having  seen  the  emphatic  experimental  results 
and  having  tried  this  technique  clinically,  cannot  say  less. 
It  matters  not  whether  the  operation  is  performed  under 
general  anaesthesia  or  under  local,  this  precaution  should 
be  taken,  inasmuch  as  it  is  true  that,  while  general  anaes- 
thesia protects  the  patient  against  pain,  it  does  not  prevent 
the  reflex  inhibition,  so  that  cocainization  serves  precisely 
as  important  a  purpose  under  general  anaesthesia  as  it 
does  under  local. 

In  the  choice  of  general  anaesthetics  the  patient  may  be 
more  quietly  and  readily  reduced  under  chloroform  than 
under  ether,  and  the  tendency  to  the  secretion  of  mucus 
is  less.  In  these  respects  chloroform  is  preferable  to  ether. 
In  another  very  important  respect  ether  is  preferable  to 
chloroform, — namely,  under  chloroform  anaesthesia  there 
is  a  decidedly  greater  tendency  towards  respiratory  failure 
and  reflex  inhibitory  phenomena  than  under  ether  anaes- 
thesia. 

This  observation  on  the  comparative  effect  of  chloro- 
form and  of  ether  is  in  full  accord  with  work  done  by 


SURGERY   OF  THE   RESPIRATORY   SYSTEM  91 

Gaskill  and  Shore,  Leonard  Hill  and  Waller,  whose  con- 
clusions, based  upon  a  large  number  of  experiments,  show 
that  chloroform  exerts  a  much  more  toxic  action  upon  the 
muscle-fibres  of  the  heart  than  does  ether,  so  that,  in  a 
given  case  of  full  chloroform  anaesthesia,  it  is  probable 
that  the  heart-muscle  is  more  easily  inhibited  than  under 
ether  anaesthesia,  producing,  as  it  does,  less  direct  toxic 
action  upon  the  heart-muscle. 

On  the  whole,  it  would  probably  be  best  to  reduce  the 
patient  to  surgical  anaesthesia  by  means  of  chloroform, 
then  continue  the  anaesthesia  under  ether,  unless  ample 
precaution  against  collapse  be  made  by  the  local  appli- 
cation of  cocaine.  Inasmuch  as  it  is  not  the  intention  of 
this  paper  to  deal  with  the  general  aspects  of  these  ques- 
tions, no  comments  will  be  made  upon  other  points  in  the 
technique  or  treatment. 

It  has  been  frequently  observed  that  if  the  foreign  body 
is  not  lodged  high  up  in  the  respiratory  tract  it  is  likely 
to  be  found  at  the  bifurcation  or  in  one  of  the  bronchi, 
most  frequently  the  left.  There  is,  it  seems  to  me,  an 
additional  explanation  for  this  fact  aside  from  that  usually 
made.  It  is  readily  demonstrable  that  the  exj^iratory 
efforts  of  the  respiratory  apparatus  are  more  powerful 
than  the  inspiratory.  It  is  necessarily  true  that  an  in- 
spiratory force  exerted  upon  a  foreign  body  cannot  exceed 
that  of  the  atmospheric  pressure  rushing  from  an  area  of 
higher  pressure  to  that  of  a  lower, — that  is  to  say,  rushing 
into  the  chest  during  the  formation  of  a  partial  vacuum 
therein.  The  expiratory  force  is  limited  only  to  the 
capacity  of  all  the  ordinary  muscles  of  respiration  plus 
that  of  all  the  extraordinary  muscles  of  respiration,  which 


92  EXPERIMENTAL   RESEARCH   INTO   THE 

collectively  include  large  groups  of  muscles,  many  of 
which  are  the  strongest  muscles  of  the  body. 

It  has  been  shown  by  experimental  physiologists  that 
the  expiratory  groups  of  muscles  are  more  powerful  than 
are  the  inspiratory.  It  follows,  then,  other  things  re- 
maining the  same,  that  a  foreign  body  subjected  to  the 
play  of  these  two  factors,  acting  in  opposite  directions, 
must  find  a  lodgement  towards  the  side  of  the  one  which 
is  weakest.  Now,  when  the  foreign  body  has  dropped 
down  so  low  as  to  become  engaged  in  one  of  the  bronchial 
tubes,  the  force  of  the  respiratory  efforts  is  only  partially 
applied  to  this  lodgement  of  the  foreign  body  because  of 
the  want  of  resistance  in  the  free  bronchial  tube ;  while, 
if  the  foreign  body  were  in  the  trachea,  the  entire  force 
of  the  expiratory  efforts  would  be  directed  against  the 
foreign  body,  and  so  would  likely  drive  it  onward  into 
the  larynx. 

On  purely  theoretic  grounds  it  would  seem  that  if  in  a 
given  case  of  lodgement  of  a  foreign  body  in  one  bronchial 
tube,  after  a  failure  of  respiratory  efforts  to  dislodge  it,  the 
free  bronchial  tube  were  closed  by  an  obturator  quickly 
applied,  so  that  the  whole  expiratory  force  might  be 
brought  to  bear  upon  both  bronchial  tubes  alike,  thereby 
increasing  to  a  great  extent  the  expulsive  force  exerted 
upon  the  foreign  body,  such  additional  force  might  occa- 
sionally dislodge  the  foreign  body  that  has  resisted  all 
other  efforts.  This,  however,  is  a  mere  theoretic  sugges- 
tion, not  founded  upon  either  direct  experimental  or 
clinical  evidence. 

In  fixing  the  trachea  with  a  hook,  and,  indeed,  in  any 
portion  of  the  technique,  it  is  of  importance  not  to  drag 


SURGERY   OF   THE   RESPIRATORY  SYSTEM  93 

from  above  downward  with  too  iriucli  force,  else  there  may 
be  produced  an  inhibitory  effect  upon  the  respiration,  and, 
if  the  force  be  very  severe,  also  upon  the  heart.  This 
does  not  so  much  apply  to  traction  from  the  lungs  up- 
ward in  the  line  of  the  tracheal  axis.  Lifting  the  trachea 
out  of  its  bed  forcibly  is  objectionable  for  the  same  reason 
that  dragging  down  too  forcibly  upon  the  trachea  should 
be  avoided. 

LAEYNGOTOMY 

PreMminary  Remarks. — ^Surgeons  have  not  infrequently 
encountered  in  performing  a  laryngotomy  a  sudden  col- 
lapse at  the  moment  when  the  incision  was  made  through 
the  larynx,  and  the  margins  of  this  incision  were  kej^t 
apart  for  the  introduction  of  the  tube.  Even  death  has 
occurred  not  infrequently  at  this  time.  Such  results  have 
been  more  frequently  encountered  in  hasty  operations,  and 
hasty  operations  for  admitting  air  into  the  tract  have  usu- 
ally been  laryngotomies.  In  the  history  of  tracheotomies, 
collapse,  or  death,  at  the  particular  stage  referred  to  above, 
have  been  rarely  observed. 

Principles  involved  in  the  Technique. — The  experi- 
mental and  clinical  evidence  set  forth  in  the  preceding- 
subject  include  all  the  principles  involved  in  such  results 
in  laryngotomy.  The  larynx  having  been  reached  in  the 
dissection,  an  incision  is  usually  made  boldly  through  it, 
and  the  margins  of  this  incision -are  held  apart,  a  pro- 
cedure in  which  there  is  a  mechanical  irritation  of  the 
dangerous  area  in  the  larynx.  This  area,  as  has  been 
shown  experimentally,  occupies  the  middle  and  uj^per 
portion  of  the  larynx.  It  is  well,  then,  if  a  laryngotomy 
must  be  made,  to  bear  in  mind  this  "  inhibition"  area  in 


94  EXPERIMENTAL   RESEARCH  INTO   THE 

tiie  larynx.  It  would  add  greatly  to  the  safety  of  the 
operation  if  the  incision  were  first  made  through  the  crico- 
thyroid space,  then  a  swab  of  cocaine  passed  through 
this  incision  and  applied  to  the  laryngeal  mucosa.  This 
having  been  well  done,  no  amount  of  manipulation  could 
cause  any  reflex  phenomena.  Likewise,  in  the  introduc- 
tion of  the  tube  in  the  high  laryngotomy,  there  would  be 
almost  certain  interference  with  the  inhibition  area  and 
the  production  of  the  usual  symptoms.  Even  though 
artificial  respirations  may  be  supplied,  it  must  be  remem- 
bered that  the  heart  may  be  inhibited  as  well.  The 
cocaine  is  an  almost  certain  preventive  of  this  cardiac 
inhibition,  yet  it  would  be  safer  to  administer  a  hypo- 
dermic injection  of  atropine  before  beginning  the  opera- 
tion. 

Treatment  of  Reflex  Phenomena  in  Laryngotomy.-— Wh^^i 
has  been  said  on  this  subject  under  intubations  may  be 
said  for  the  treatment  of  like  conditions  in  this  operation. 

TRACHEOTOMY 

Preliminary  Remarks. — I  am  unaware  of  instances  of 
sudden  collapse  or  death  in  the  technique  for  tracheotomy 
due  to  other  causes  than  the  obstruction  for  which  the 
operation  was  performed, — that  is  to  say,  the  collapse  and 
death  which  occasionally  follow  intubation  and  laryn- 
gotomy do  not  follow  the  performance  of  tracheotomy. 

Experimental. — Animals  under  surgical  anaesthesia  were 
subjected  to  the  following  experiments :  The  trachea  was 
submitted  to  dilatation  of  different  degrees,  ranging  from 
gentle  dilatation  to  a  sufficient  force  to  rupture  that 
organ,  and  in  not  a  single  instance  was  there  noted  any 


SURGERY   OF  THE   RP]SPIRATORY   SYSTEM  95 

marked  change  in  either  the  respiration  or  the  circula- 
tion. All  portions  of  the  trachea  from  the  larynx  down 
were  tested,  and  in  all  the  cases  the  results  were  similar. 
The  only  variations  observed  were  in  some  cases  an  in- 
creased respiratory  rhythm  with  an  increase  in  the  ampli- 
tude of  the  respirations,  and  in  some  instances  there  was 
slight  increase  in  the  blood-pressure  without  any  altera- 
tion in  the  character  of  the  cardiac  action.  In  several 
instances  there  was  a  slight  decline  in  blood-pressure.  It 
appeared  that  these  several  minor  alterations  in  the 
blood-pressure  and  the  respiration  were  due  to  mechan- 
ical stimulation  of  sensory  tissue  having  a  direct  connec- 
tion with  the  inhibitory  apparatus  of  either  the  respira- 
tory or  the  cardiac  apparatus.  From  an  experimental 
stand-point  it  would  seem  to  be  impossible  to  produce 
sudden  death  in  any  such  manner  as  it  may  be  produced 
in  operations  involving  the  larynx  and  certain  portions  of 
the  pharynx. 

The  experiments  upon  the  trachea  were  made  in  ani- 
mals upon  which  experiments  were  being  made  for  other 
purposes,  and  consequently  they  are  not  recorded  sepa- 
rately. 

Practical  Application. — The  result  of  these  experiments 
is  of  practical  importance  mainly  in  pointing  out  the  very 
great  safety  of  operative  procedures,  so  far  as  the  imme- 
diate results  are  concerned,  upon  th.e  trachea  as  compared 
with  like  operations  upon  the  larynx, — that  is  to  say,  in 
considering  the  choice  of  tracheotomy  or  laryngotomy 
the  principles  involved  in  the  two  operations  would  be  of 
great  value  in  making  a  choice. 


96  EXPERIMENTAL   RESEARCH   INTO   THE 

IlfTUBATION 

Preliminary  Remarks. — In  performing  intubations  not 
infrequently  cases  of  sudden  collapse  or  death  are  encoun- 
tered. These  results  appear  with  such  suddenness  as  to 
give  but  little  time  for  thought  or  action,  and  it  would  be 
a  matter  of  great  interest  to  those  who  perform  such 
operations  to  know  by  what  means  such  results  are  pro- 
duced. In  my  own  experience,  in  a  series  of  sixty-five 
intubations,  there  were  three  such  sudden  deaths.  While 
different  theories  have  been  proposed  in  explanation,  none 
have,  so  far  as  I  am  aware,  been  founded  on  any  consider- 
able experimental  evidence.  The  results  are  most  fre- 
quently attributed  to  sudden  suffocation  from  forcing 
down  into  the  air-passage  detached  membranes.  Others 
have  said  that  the  cases  die  of  collapse,  which  is,  of  course, 
not  an  explanation.  It  has  been  asserted  that  the  deaths 
are  due  to  reflex  phenomena  from  irritation,  but  the 
method  of  the  production  of  these  phenomena  is  not 
pointed  out. 

Protocols. — 1.  Healthy  fox-terrier,  weight  twenty  pounds, 
under  full  surgical  ether  anaesthesia,  with  the  respiratory 
apparatus  marking  the  blood-pressure  taken  in  the  carotid 
artery.  After  obtaining  a  control  tracing,  the  larynx 
was  dilated  in  a  manner  as  nearly  as  possible  like  that 
of  introducing  a  tube  in  intubation.  The  result  of  the 
careful  introduction  was  merely  a  temporary  inhibition 
of  respirations.  After  a  few  feeble  respiratory  efforts, 
whose  intervals  were  prolonged,  normal  respiratory  rhythm 
was  again  established.  However,  when  the  tube  was 
dragged  forward  with  some  force,  so  that  its  lower  end 


SUKGEllY    OF   THK    JlKSPIIiATOI'v Y    SVSTKM 


97 


'■lif{l!'Mf!J^!^{r-.f.''''^! 


pushed  backward  against  the  rinia  of"  the  larynx  and  its 
upper  end  pressed  forward  against  the  rima  glottidis,  a 
more  marked  respiratory  failure  was  produced,  the  carotid 
manometer  executed  long,  sweeping  strokes,  and  the  blood- 
pressure  during  this  time  fell.  On  continuing  the  manip- 
ulation for  some  time  a  fair 
degree  of  tolerance  was  ac- 
quired, and  the  foregoing  phe- 
nomena appeared  in  but  a 
slight  degree, — that  is  to  say, 
the  heart-strokes  were  a  little 
longer  and  a  little  slower  than 
normal,  and  the  respirations 
were  shorter,  with  a  longer 
pause. 

2.  An  old  collie-dog,  weight 
eighteen  pounds,  with  the 
same  arrangements  for  graph- 
ic records  as  in  the  preceding. 
A  tube  was  introduced  with 
gentleness  into  the  larynx, 
then  an  attempt  was  made  by 
exerting  forcible  manipula- 
tion upon  the  exterior  of  the 
larynx  to  force  the  tube  out 
of  the  larynx  into  the  mouth.  This  rude  manipulation 
produced  an  arrest  of  respiration  with  a  marked  fall  in 
the  blood-pressure,  the  heart-strokes  being  much  slowed. 
On  cessation  of  the  manipulation,  after  the  tube  had  been 
forced  out,  the  respiratory  and  circulatory  mechanisms 
resumed  their  normal  action. 

7 


19.  Experiment  on  Intubation, 
roughly  made,  and  foreign  body  in 
THE  Pharynx.— The  upper  tracing  repre- 
sents the  respiration,  the  next  the  blood- 
pressure,  and  the  lower  two  the  time  aud 
the  signal  respectively. 


98  EXPERIMENTAL   RESEARCH   INTO  THE 

3.  A  mongrel  cur,  weight  twenty  pounds,  witli  pre- 
liminary preparation  as  in  the  preceding  case,  was  so 
placed  upon  the  dog-board  as  to  bring  his  mouth  into 
a  position  convenient  for  the  introduction  of  the  fingers 
into  the  pharynx  and  the  tilting  the  epiglottis  forward 
with  gentleness.  In  so  doing  there  was  but  little  disturb- 
ance in  the  respiratory  and  the  circulatory  tracings.  The 
only  alteration  noted  was  in  a  single  partial  respiratory 
inhibition.  The  heart  was  not  at  all  affected.  Then, 
allowing  a  good  control  of  tracings  to  be  made,  the  fingers 
were  again  introduced,  and  with  considerable  roughness 
and  force  dragged  forward  the  epiglottis,  and  with  it  the 
base  of  the  tongue  and  larynx,  imitating  a  vigorous  effort 
to  dislodge  membrane  or  recover  a  tube  in  certain  catas- 
trophes, which  occasionally  attend  the  operation  of  intu- 
bation. Immediately  upon  so  manipulating  the  parts 
there  was  a  respiratory  arrest  and  the  heart  was  inhibited, 
causing  a  staggering,  temporary  fall  in  the  blood-pressure 
and  the  appearance  of  "  vagal"  beats.  On  repeating  such 
vigorous  manipulations  at  short  intervals  a  less  marked 
effect  on  each  repetition  was  observed,  until,  finally,  when 
the  animal  had  become  quite  exhausted,  but  little  effect 
was  produced. 

4.  With  preliminary  preparation  as  in  the  preceding 
case,  the  diaphragm  was  exposed  by  a  median  incision, 
and  the  stomach  and  the  liver  so  withdrawn  as  to  permit 
direct  observations.  The  larynx  was  now  subjected  to 
severe  manipulation  by  passing  the  finger,  through  an  in- 
cision between  the  upper  ring  of  the  trachea  and  the 
cricoid,  into  the  larynx  and  making  pressure  between 
this  finger  so  placed  and  the  thumb  upon  the  exterior, 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  99 

producing  thereby  inliibition  of  the  respiration  and  the 
cardiac  action  as  before.  Observations  upon  the  dia- 
phragm during  this  time  showed  tliis  organ  to  be  in  re- 
laxation. The  skin  was  then  so  removed  from  the  chest 
as  to  expose  the  muscles  of  respiration,  and  the  foregoing 
experiment  again  performed.  Direct  observation  showed 
that  the  muscles  were  in  a  state  of  relaxation.  No  re- 
spiratory muscle  was  observed  to  be  in  a  state  of  tetanic 
contraction.  On  section  of  both  vagi  the  respiratory  phe- 
nomena appeared  as  before,  but  the  cardiac  remained 
normal. 

5.  A  shepherd-dog,  twenty-five  pounds  in  weight,  pre- 
liminary preparations  as  in  the  preceding  case.  The 
various  phenomena  w^ere  again  produced  by  like  pro- 
cedures. On  painting  the  laryngeal  mucosa  with  four 
per  cent,  solution  of  cocaine,  then  repeating  the  intra- 
laryngeal  manipulation,  no  inhibition  of  either  the  res- 
piration or  of  the  heart  was  observed. 

6.  A  mongrel,  weight  twenty-one  and  one-half  pounds, 
preparations  as  before.  After  securing  control  inhibi- 
tions by  manipulations  as  in  preceding  experiments,  one- 
one-hundredth  of  a  grain  of  atropine  was  injected  into 
the  jugular  vein.  Almost  immediately  following  this 
there  was  a  rise  in  the  blood-pressure  and  the  manometer 
strokes  were  shortened,  indicating  the  loss  of  "  vagal"  in- 
fluence. Then,  on  repeating  the  procedures  described  in 
the  foregoing  experiments,  the  respirations  were  arrested 
as  before,  but  the  blood-pressure  remained  unaffected. 
On  severing  the  superior  laryngeal  nerves,  then  repeat- 
ing the  laryngeal  manipulations,  no  respiratory  inhibi- 
tion followed. 


100  EXPERIMENTAL  RESEARCH   INTO   THE 

Summary  of  Experimental  Evidence. — These  experi- 
ments show  that  the  reflex  inhibition  is  due  to  efferent 
impulses  set  up  by  mechanic  irritation  of  the  terminals 
of  the  superior  laryngeal  nerves. 

CLINICAL   OBSERVATIONS 

The  Effect  upon  Respiration. — In  almost  every  case  of 
intubation  there  is  at  least  a  temporary  inhibition  of  res- 
piration in  a  manner  and  to  a  degree  entirely  comparable 
to  that  obtained  by  experiments  on  animals.  The  extent 
of  this  inhibition  depends  upon  the  following  factors :  In 
cases  in  which  the  laryngeal  mucosa  is  completely  pro- 
tected by  a  closely  adherent  membrane,  reflex  inhibition 
of  respiration  is  observed  to  be  the  least  marked.  In 
cases  in  which  the  membranes  have  disappeared,  and  the 
surface  is  raw  and  has  been  subjected  to  much  irritation, 
like  procedures  produce  a  more  marked  reflex  inhibition. 

I  have  made  these  observations  in  a  number  of  cases 
clinically.  It  need  hardly  be  said  that  the  extent  of  in- 
hibition is  also  in  direct  ratio  to  the  amount  of  mechanic 
irritation  produced  by  the  placing  of  the  tube.  The 
greater  the  irritation,  the  greater  the  inhibition.  In  a 
child  poisoned  with  toxins,  and  with  but  little  vitality, 
inhibition  may  not  be  more  marked  at  its  very  onset, 
but  recovery  of  the  normal  state  does  not  so  readily 
follow. 

Effect  upon  the  Cardiac  Action. — In  a  number  of  in- 
stances in  which  direct  observations  upon  the  pulse  were 
made  during  the  introduction  of  the  tube,  an  inhibitory 
effect  upon  the  heart  was  occasionally  observed.  The 
cardiac  inhibition  is,  however,  not  nearly  so  frequently 


SURGERY   OF   THE   KESPTRATORY   SYSTEM         101 

observed  as  the  respiratory,  and  wliat  lias  been  said  as 
to  the  variations  of  the  respiratory  inliibition  may  be 
said  equally  of  the  cardiac. 

Collapse  and  Death  due  to  Inhibition. — From  the  ex- 
perimental and  the  clinical  evidence  at  hand  it  is  evident 
that  collapse  and  death  in  intubation  are  due  to  the  reflex 
inhibition  of  the  respiration  and  of  the  heart,  from  me- 
chanic stimulation  of  the  superior  laryngeal  nerves  in 
the  manipulation  of  the  tube.  The  onset  of  the  symp- 
toms is  sudden.  The  patient  at  once  becomes  limp  and 
lifeless,  the  face  becomes  livid,  the  pulse  has  disappeared 
from  the  wrist,  respirations  have  ceased,  and  the  child  is 
dead. 

In  cases  less  severe  the  child  suddenly  goes  into  a  col- 
lapse characterized  by  its  becoming  suddenly  relaxed  in 
the  midst  of  a  struggle  while  the  tube  is  being  placed, 
the  respiration  ceasing,  and  the  pulse  not  being  percep- 
tible at  the  wrist.  However,  after  a  brief  pause,  respira- 
tion slowly  resumes,  the  pulse  may  be  felt,  weak  and 
slow,  but  gradually  growing  stronger,  and  in  a  few  min- 
utes respiration  and  the  cardiac  action  are  again  restored. 
The  most  marked  characteristic  is  the  absolute  sudden- 
ness of  the  cessation  of  the  respiratory  and  the  cardiac 
action. 

Differential  Diag7iosis  between  Obstruction  from  3Iem- 
branes  pushed  dotvn  and  Collapse  from  Reflex  Inhibition. 
— In  asphyxia  from  pushing  down  the  membranes  the 
characteristic  symptoms  are  the  deep  cyanosis,  slow  but 
full  pulse,  and  continued  respiratory  efforts  for  a  short 
time.  In  a  case  of  pure  asphj^^xia  from  obstruction,  re- 
spiratory efforts  do  not  suddenly  cease.     In  collapse  from 


102 


EXPERIMENTAL   RESEARCH   INTO  THE 


(P  O)  „•  (U 

r3  ti  C  rt 

£  ^  _o  S 

°  -^  s  s 

<J>  ■S  'S  fe 


m     .  «*-i  "" 

"  "O   o  -S 

«"    a)    m    S 

O  ii    0)    2 

time 
y  mar 
muscl 

Cont 

a)   h    , 

^     01    >>  -tJ 

^   t>   g   § 

SB   «     C   — 

howin 
troke  i 
raordi 
to  the 

^    ^M^ 

oj    C   4)    te 

CO     M     +J 

y  the 
respi 
•yall 
ather 

,1-,   a>  05   K 

1  5   ft-rt 

•5:  <B  .5    >. 

(absci 
e  inert 
ringin 

regul: 

2  fl  -"  i2 
e  -^  ^  ^ 

S    •-   03    01 

,Q    0    ai     oj 

n  the 
tory  a 
;,  the  1 
he  he 

a'    03   ■5  H 

fl  s  S 

*1'P.'^      - 

isure 
eres 
1  the 
llure 

£52^ 

£L    rt    --     U 
jT-S     0     03 

rH              6»^    tH 

0  S  frt  "C 

®  s  S  S 

Q)      0      P.r-1 

^     G     _     03 

53   -rt    rt    j3 

*^    fQ    *_»    'O 

«»    rt    03 

01  ^  a  t* 

a  i:;  <u  M 

"    Hi    ^^ 

,the 
■y  m; 
hey 
,  the 

ation 
le  vei 
but  t 
ssure 

i-i  ■H    -  01 

•'-    -►^   «    n 

5-  •a  a  A 

sres 
Not 
que 

30d- 

■"              JU    1^ 

fi       •    cS    -Q 

M    "O      S      01 

£  fi  s  a 

p.  0  ^  ■" 

2  S  <u  fl 

cing: 
3  in  s 
ecom 
rise  i 

bi) 

g 

'S 

1  a-:  >> 

0 

upper 
d  the  t: 
stroke; 
mpora 

! 

oj  c  01  -2 

§ 

■fi  "^  -a  «, 

t-i      ►  +3    0) 
^     o3          ^ 

a 

.    0)    01    *3 

•^ 

<^   '§    fi    5 

<u 

p. 

o3   ^    0 

2 

SURGERY   OK   THE   RESPIRATORY   SYSTEM  10:^> 

reflex  inhibition  the  pulse  disappears  from  the  wrist,  the 
heart-beats,  if  observable  at  all,  are  very  slow  and  weak. 
In  asphyxia  the  heart-beats  grow  temporarily  actually 
stronger.  In  reflex  inhibition  death  may  instantly  ensue. 
In  asphyxia  it  cannot. 

In  asphyxia  from  obstructing  membranes,  cyanosis  is 
much  more  marked  than  in  reflex  inhibition.  In  reflex 
inhibition,  when  very  profound,  there  may  be  a  sudden 
pallor  on  account  of  the  total  sudden  failure  of  the  circu- 
lation. There  is  an  abundance  of  experimental  evidence, 
and  physiologists  are  agreed  that  the  blood-pressure  in 
asphyxia  rises,  that  the  heart-beats  become  stronger  and 
slower,  and  there  is  clinical  evidence  entirely  in  accord 
with  that  of  the  experimental  physiologists.  The  quick 
perception  of  the  diflerence  between  these  two  conditions 
is  of  the  utmost  importance  in  the  conduct  of  the  case,  as 
will  be  more  fully  pointed  out  directly. 

Prevention  of  Collapse  from  Reflex  Inhibition. — So  far 
as  the  heart  is  concerned  reflex  inhibition  may  be  wholly 
prevented  by  a  preliminary  hypodermic  injection  of  atro- 
pine. This  drug,  as  is  well  known,  paralyzes  the  nerve- 
endings  of  the  vagi  in  the  heart,  thereby  protecting  this 
organ  against  reflex  inhibitory  impulses.  Or  the  local 
application  of  cocaine  upon  the  laryngeal  mucosa  may 
prevent  not  only  the  reflex  inhibition  of  the  heart,  but  of 
the  respiration  as  well. 

The  Treatment  of  Chllapse  from  Reflex  Inhibition. — It 
is  now  my  practice  so  to  arrange  the  clothing  of  the  pa- 
tient, before  performing  the  operation  of  intubation,  that 
ready  access  to  the  chest  and  the  abdomen  is  provided, 
and  that  a  towel  and  a  basin  of  cold  water  are  at  hand. 


104  EXPERIMENTAL  RESEARCH   INTO   THE 

On  the  appearance  of  collapse  the  patient  is  inclined, 
head  downward,  and  artificial  respiration  maintained. 
In  the  mean  time  the  chest  and  abdomen  are  smartly- 
struck  with  a  cold,  wet  towel.  Immediately  after  this 
slapping,  the  surface  is  dried  and  the  slapping  again  re- 
peated. Cold  water  smartly  applied  to  the  surface  of  the 
skin  is  one  of  the  most  powerful  respiratory  stimulants, 
and  an  inspiratory  effort  is  always  first  brought  out  on 
such  treatment.  Further  than  this  there  is  little  to  be 
done.  There  is  no  time  for  medication.  It  will  be  at 
once  seen  how  important  it  is  to  recognize  the  difference 
between  collapse  produced  in  such  manner  and  asphyxia 
from  forcing  down  membrane.  Suppose  in  a  given  case 
of  collapse  from  reflex  inhibition  it  was  believed  that 
membrane  had  been  forced  down,  the  tube  having  been 
placed  in  the  larynx,  hasty  efforts  would  be  immediately 
directed  towards  relieving  the  respiratory  tract  of  this 
obstruction.  Such  efforts  would  consist  naturally  of  an 
attempt  hastily  to  remove  the  tube,  and  the  efforts  at 
relief  would  by  further  stimulation  of  this  inhibition  area 
in  the  larynx  cause  an  increase  in  the  very  condition  the 
operator  was  seeking  to  relieve.  And,  furthermore,  the 
blood-pressure  having  sunk  almost  to  zero,  the  patient, 
instead  of  being  inclined  head  downward,  may  be  kept 
in  the  sitting  posture  while  attempts  at  relieving  the 
obstruction  are  being  made.  And,  finally,  it  is  doubtful, 
in  consideration  of  the  extraordinary  expulsive  power  of 
the  respiratory  apparatus,  whether  a  membrane  may  be 
detached  and  so  firmly  lodged  below  a  tube  as  to  cause 
an  obstruction  after  removal  of  the  tube. 

If  clinicians  will  take  a  retrospect  of  the  cases  in  which 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  105 

such  an  obstruction  was  supposed  to  exist,  they  will  prob- 
ably be  enabled  to  recall  no  great  respiratory  efforts  on 
the  part  of  their  patients.  In  the  presence  of  so  appalling 
a  catastrophe,  calm  observations  are  by  no  means,  as  a 
rule,  made,  and  if  every  case  were  approached  with  the 
deliberate  intention  of  making  correct  observations,  there 
would  probably  not  be  a  mistake  in  confusing  obstruction 
with  reflex  inhibition,  and  it  would  be  found  that  nearly 
all  the  cases  of  so-called  obstruction  are  cases  of  reflex  in- 
hibition. In  one  case  occurring  in  my  own  practice,  in 
which  the  child  went  into  collapse  while  introducing  a 
tube  in  a  second  intubation,  the  child  was  handed  to  one 
assistant,  another  kept  up  artificial  respiration,  while  I 
made  clinical  observations  of  the  phenomena.  Placing 
my  ear  to  its  chest,  I  heard  faint,  slow  heart-beats,  soon 
becoming  louder  and  more  rapid  as  the  child  rapidly  re- 
gained consciousness.  This  case  was  a  repetition  in  its 
every  phase  clinically  of  the  inhibition  phenomena  experi- 
mentally produced. 

EXPERIMENTAL  RESEARCH  INTO  THE  CAUSE  OF  CERTAIN 
PHENOMENA  ATTENDING  CONSIDERABLE  TRACTION  ON 
THE    TONGUE 

Preliminary  Remarks. — On  several  occasions  I  have 
observed  an  immediate  cyanosis  and  very  considerable 
collapse  attending  vigorous  traction  on  the  tongue  on  the 
part  of  an  over-zealous  ansesthetizer,  in  his  efforts  to  re- 
lieve the  patient  from  the  obstruction  due  to  the  reces- 
sion of  the  tongue  upon  the  laryngeal  opening.  While 
before  this  vigorous  traction  there  were  respiratory  efforts 
(though  futile,  on  account  of  the  mechanical  obstruction 


106  EXPERIMENTAL  RESEARCH   INTO   THE 

alluded  to),  during  and  immediately  following  the  trac- 
tion there  was  complete  cessation  of  respiration  for  a  brief 
interval,  then  slow  and  shallow  respiratory  efforts,  which 
finally  and  gradually  became  vigorous  again.  The  pulse 
meanwhile  was  weak  and  slow ;  in  short,  the  patients  were 
in  temporary  collapse.  It  was  a  matter  of  doubt  as  to 
whether  or  not  the  phenomena  described  were  due  to 
the  ansesthetic. 

Protocols. — 1.  On  a  twenty-pound  shepherd-dog,  under 
ether  ansesthesia,  with  initial  blood-pressure  at  one  hun- 
dred and  twenty  millimetres,  the  following  experiments 
were  performed :  The  upper  jaw  was  fixed  firmly  upon 
the  dog-board,  the  lower  jaw  was  held  widely  open,  the 
tongue  was  grasped  with  three  Well's  forceps ;  this  pro- 
duced no  effect  upon  either  Respiration  or  the  blood- 
pressure.  Gentle  traction  was  then  made  in  the  line  of 
the  axis  of  the  tongue,  during  which  the  blood-pressure 
and  the  respiratory  action  remained  unchanged ;  then, 
suddenly  applying  forcible  traction,  the  heart  was  tempo- 
rarily arrested,  producing  a  staggering  fall  in  the  blood- 
pressure  ;  following  this  temporary  inhibition  of  the  heart, 
there  were  slow,  vagal  strokes,  gradually  returning  to  the 
normal  action.  In  the  mean  time  the  blood-pressure  rose 
to  the  level  it  was  before,  simultaneously  with  the  arrest  of 
the  heart,  the  respirations  were  completely  stopped  during 
the  application  of  the  severe  traction.  On  releasing  the 
tongue,  the  respirations  were  again  resumed,  at  first  more 
slowly,  finally  in  the  normal  manner.  The  lower  jaw 
was  then  sawn  in  the  median  line  and  the  lateral  halves 
were  separated  as  far  as  possible,  producing  thereby  a 
marked  fall  in  the  blood-pressure,  the  heart  showing  dis- 


SUllGERY   OF   THE   RESPIRATORY   SYSTEM  107 

tinct  vagal  influence;  the  respirations  meanwhile,  after 
suffering  a  temporary  arrest,  resumed  slowly  their  normal 
action.  The  effects  were  similar  to  those  produced  by 
the  severe  traction  on  the  tongue,  though  less  in  degree. 
The  first  experiment  of  traction  upon  the  tongue  was 
twice  repeated,  each  time  yielding  practically  the  same 
results. 

2.  On  a  Newfoundland  dog  weighing  forty-five  pounds, 
under  ether  anaesthesia,  with  an  initial  blood-pressure  at 
one  hundred  and  fifty  millimetres,  the  following  experi- 
ments were  performed :  The  tongue  was  drawn  out  and 
securely  tied  with  a  heavy  cord  near  the  frsenum ;  the 
blood-pressure  and  respiration  meanwhile  remained  un- 
altered. With  the  aid  of  this  string  and  three  Well's 
forceps,  the  tongue  was  gradually  subjected  to  a  traction 
along  the  line  of  its  own  axis.  In  the  first  part  of  the  trac- 
tion no  effects  were  observed.  On  the  application  of  greater 
force  the  heart  was  very  much  slowed,  the  blood-pressure 
suffered  a  slight  decline,  and  the  respirations  were  greatly 
diminished  in  the  amplitude  of  their  stroke  and  in  their 
frequency ;  on  applying  a  still  greater  traction,  the  heart 
was  temporarily  arrested,  as  was  the  respiration  also  ;  then 
the  lower  jaw  was  opened  with  great  force  as  widely  as  pos- 
sible, and  finally  cardiac  and  respiratory  effects  similar  to 
those  observed  in  the  preceding  case,  though  to  a  less  de- 
gree, were  produced.  The  traction  phenomena  were  twice 
produced  by  repeating  the  technique  above  described. 

3.  On  a  twenty-pound  fox-terrier,  with  an  initial  blood- 
pressure  of  one  hundred  and  forty  millimetres,  under 
chloroform  anaesthesia,  the  following  experiments  were 
performed :    The  tongue  was  drawn  out  in  the  manner 


108 


EXPERIMENTAL   RESEARCH   INTO  THE 


mmmmmn 


previously  described,  then  suddenly  drawn  across  the 
angle  of  the  mouth,  thereby  producing  complete  arrest  of 
the  heart's  action  as  well  as  of  respiration,  with  a  con- 
sequent collapse  in  the  blood-pressure  almost  to  the  ab- 
scissa line.  This  manceuvre  was 
repeated  a  number  of  times  in 
rapid  succession,  each  time  pro- 
ducing similar  effects  upon  the 
cardiac  action  and  the  respira- 
tion, finally  resulting  in  very 
great  collapse,  from  which  the 
animal  did  not  recover. 

4.  On  a  fat  poodle  weighing 
twelve  pounds  the  preceding 
technique  was  carried  out  as 
nearly  as  possible  in  every  de- 
tail, with  results  practically  the 
same. 

5.  On  a  twenty-four-pound 
mongrel  under  chloroform  anses- 
thesia,  with  initial  blood-pressure 
of  one  hundred  and  sixty  milli- 
metres, the  various  kinds  of 
traction  were  applied,  producing 
a  most  profound  collapse  by  tem- 
porarily inhibiting  both  the  heart 

and  the  respiration.  A  piece  of  gauze  was  then  thrust 
down  very  roughly  into  the  pharynx,  in  imitation  of 
clearing  out  the  throat  during  the  administration  of  an 
anaesthetic.  This  produced  a  temporary  arrest  of  respi- 
ration, but  no  effect  upon  the  heart's  action. 


'^rtuOwK.  f^'ttntAMJ. 


21.  Traction  ON  THE  Tongue. — 
The  upper  tracing  represents  the 
respiration,  the  next  the  hlood- 
pressure.  Note  the  temporary  in- 
hibition of  both  during  forcible 
traction.  This  was  the  most 
marked  effect  produced  in  any  of 
the  experiments. 


SURGERY   OF   THE   RESPIRATORY   SYSTEM  109 

6.  On  a  fox-terrier  weighing  twenty-two  pounds,  under 
chloroform  anaesthesia,  the  following  experiments  were 
performed :  The  tongue  was  subjected  to  traction,  as  in 
the  preceding  experiments,  producing  the  usual  phenom- 
ena, after  which  one-one-hundredth  of  a  grain  of  atropine 
was  injected  into  the  jugular  vein.  This  occasioned  an 
immediate  rise  in  the  blood-pressure  and  an  increase  in 
the  frequency  of  the  heart-beats,  indicating  the  release  of 
the  heart  from  the  influence  of  the  vagi.  The  left  vagus 
was  then  exposed  and  the  efficiency  of  the  atroj^ine  tested 
by  applying  faradic  stimulation ;  the  stimulation  did  not 
affect  the  cardiac  action,  which  proved  the  efficiency  of 
the  atropine.  The  tongue  was  then  subjected  to  traction 
in  the  same  manner,  and,  as  nearly  as  possible,  to  the 
same  degree  as  in  the  preceding  experiments.  Although 
this  traction  was  repeated  several  times  in  various  direc- 
tions, instead  of  a  fall  in  the  blood-pressure  there  was 
produced  a  temporary  rise.  The  respirations,  however, 
were  arrested  as  in  the  previous  experiments.  The  lower 
jaw  was  then  severed,  and  the  lateral  halves  were  widely 
separated,  producing  a  rise  in  blood-pressure. 

7.  On  a  bull-dog  weighing  forty-eight  pounds,  under 
chloroform  anaesthesia,  with  initial  blood-pressure  at  one 
hundred  and  fifty  millimetres,  the  following  experiments 
were  performed :  The  anaesthesia,  during  the  preparation 
of  the  animal,  was  too  profound,  and  artificial  respirations 
became  necessary.  Before  tlie  animal  was  completely 
anaesthetized  the  jaws  were  held  apart  and  a  severe  trac- 
tion across  the  angle  of  the  mouth  was  made  upon  the 
tongue.  Although  the  respirations  were  rapid  at  the  time 
it  was  made,  they  wholly  ceased,  until  the  animal  became 


110  EXPERIMENTAL  RESEARCH   INTO   THE 

very  cyanotic  under  the  influence  of  the  powerful  traction. 
The  heart  was  simultaneously  arrested,  and  the  blood- 
pressure  collapsed.  A  physiological  dose  of  atropine,  with 
the  same  proof  of  efficiency  as  in  the  preceding  case,  was 
injected.  The  tongue  was  again  subjected  to  a  similar 
experiment,  but  the  traction  produced  no  fall  in  the 
blood-pressure,  although  the  respirations  were  effected  as 
in  the  preceding  case.  This  was  several  times  repeated 
with  similar  results. 

8.  On  an  animal  weighing  thirty  pounds,  with  initial 
blood-pressure  at  one  hundred  and  sixty-five  millimetres, 
a  control  was  made,  whereby  the  respiratory  and  the  cir- 
culatory phenomena  were  produced  as  usual.  Then  both 
vagi  were  severed,  and  a  similar  procedure  repeated.  But 
in  this  case,  as  in  the  atropine  experiment,  the  cardiac 
symptoms  did  not  appear,  although  the  respiratory  arrest 
was  as  striking  as  before.  This  was  repeated  several  times 
with  practically  the  same  results.  The  jaw  was  severed 
and  separated,  as  in  the  previous  experiment,  producing 
thereby  essentially  similar  results. 

9.  On  a  thirty-five-pound  mongrel,  under  chloroform 
ansesthesia,  with  initial  blood-pressure  of  one  hundred  and 
seventy  millimetres,  the  following  experiments  were  per- 
formed :  A  control  was  first  secured  in  the  usual  way, 
producing  the  ordinary  respiratory  and  circulatory  phe- 
nomena. The  superior  laryngeal  nerves  were  then  both 
severed,  and  the  preceding  experiment  repeated.  The 
effect  upon  the  respiration  was  wholly  prevented,  but  the 
blood-pressure  fell  as  before,  the  heart  exhibiting  strokes 
similar  to  those  observed  in  the  preceding  case.  Then  the 
glossopharyngeal  nerves  were  both  severed,  and  the  same 


SURGERY    OF   TIIK    RKSIMRATORY    SYSTKM  111 

experiment  of  traction  upon  the  tongue  repeated.  The 
respirations  were  not  at  all  affected,  but  the  heart  was  in- 
hibited, and  the  blood-pressure  fell,  as  in  the  preceding 
case.  Finally,  the  glossopharyngeal  nerves  were  both 
severed  near  their  exit  from  the  cranium.  The  tongue 
was  then  subjected  to  traction,  as  before,  with  the  result 
of  arresting  the  heart,  without  in  the  least  influencing  the 
respiration.  Finally,  both  vagi  were  severed,  and  similar 
experiments  were  performed.  Neither  the  cardiac  nor  the 
respiratory  action  was  now  in  the  slightest  degree  affected. 

10.  In  this  experiment  the  technique  and  plan  de- 
scribed in  the  ninth  were  carried  out  as  nearly  as  pos- 
sible,  resulting  in  essentially  the  same  observations. 

In  a  number  of  other  experiments  the  effects  of  traction 
upon  the  tongue  were  tried,  and  in  a  few  cases  slight 
traction  produced  a  slight  rise  in  the  blood-pressure.  In 
one  instance,  no  effect  was  produced  on  either  the  respira- 
tion or  the  heart. 

Summm^y  of  Experimental  Evidence. — When  any  effect 
was  observed  from  traction  of  moderate  degree,  it  was 
usually  a  slight  rise  in  blood-pressure,  though  generally 
such  traction  produced  no  effect. 

In  most  animals  following  considerable  traction,  more 
especially  when  the  force  was  so  applied  as  to  drag  the 
tongue  out  at  the  angle  of  the  mouth,  there  were  varying 
degrees  of  fall  in  the  blood-pressure,  ranging  from  a  com- 
plete temporary  cardiac  arrest,  with  an  enormous  fall  in 
pressure  quite  to  the  abscissa  line  in  several  experiments, 
to  a  series  of  slowed  beats  with  but  slight  actual  fall  of 
the  mean  pressure. 

Then,  again,  there  would  be  an  intermission  of  one  or 


112  EXPERIMENTAL  RESEARCH   INTO   THE 

more  beats  with  rapid  recovery  of  the  lost  pressure.  In 
some  experiments  no  effect  was  produced  on  applying  the 
traction. 

The  effect  on  resjDiration  was  to  cause  in  many  in- 
stances total  temporary  arrest ;  in  a  lesser  number  there 
was  a  decrease  in  the  rapidity  as  well  as  in  the  amplitude. 

Occasionally  no  respiratory  alterations  were  produced. 

Preliminary  injections  of  a  physiologic  dose  of  atropine 
prevented  the  cardiac  phenomena,  but  not  the  respiratory. 
Like  results  were  obtained  by  preliminary  section  of  the 
vagi. 

A  sufficient  traction  on  the  tongue  usually  causes  inhi- 
bition of  the  respiratory  and  the  cardiac  action,  the  in- 
tensity of  the  inhibition  ranging  from  a  slowed  action  to 
complete  arrest. 

The  effect  upon  the  blood-pressure  and  the  respiration 
was  at  first  believed  to  be  wholly  due  to  mechanic  stimu- 
lation of  the  superior  laryngeal  nerves.  However,  when 
these  nerves  were  severed  the  respiratory  phenomena 
were  entirely  prevented,  but  the  heart  exhibited  the 
same  inhibition  as  before. 

Section  of  the  vagi  prevented  this  effect  ujDon  the 
heart ;  the  effect  was,  therefore,  through  the  vagus.  All 
the  nerves  supplying  this  region  were  in  turn  severed, 
but  the  effect  upon  the  heart  was  not  thereby  prevented. 
We  therefore  concluded  that  the  action  upon  the  heart 
was  due,  at  least  in  part,  to  a  stimulation  of  the  vagus  by 
dragging  upon  the  structures  in  such  close  anatomic  rela- 
tion with  it  as  to  produce  thereby  a  mechanical  stimula- 
tion upon  them. 

On  making  a  dissection  of  this  portion  of  the  neck  and 


SURGERY   OF  TTTE   RESPIRATORY   SYSTEM  IKi 

observing  the  effects  of  traction  on  the  tongue,  such  re- 
sults were  clearly  seen  to  have  occurred.  Mechanic  stim- 
ulation by  dragging  directly  upon  the  vagus  may  produce 
an  effect  upon  .the  heart  quite  similar  to  the  effects  de- 
scribed in  the  protocols.  The  effect  upon  the  respiration 
was  due  to  a  mechanic  stimulation  of  the  superior  laryn- 
geal nerves. 

Praetieal  Applications. — These  results  are  of  great  prac- 
tical importance  in  the  routine  work  of  anaesthesia.  A 
thorough  appreciation  of  the  inhibitory  phenomena  pro- 
duced by  excessive  traction,  would  enable  the  ansesthe- 
tizer  to  prevent  their  appearance  and  the  surgeon  to  more 
intelligently  meet  them  when  they  do  occur. 


THE    END 


COLUMBIA  UNIVERSITY  LIBRARIES 

This  book  is  due  on  the  date  indicated  below,  or  at  the 
expiration  of  a  definite  period  after  the  date  of  borrowing, 
as  provided  by  the  library  rules  or  by  special  arrangement 
with  the  Librarian  in  charge. 


DATE  BORROWED 

DATE  DUE 

DATE  BORROWED 

DATE  DUE 

nt  :-■     ■ 

V\ 

.^ 

\\^ 

'         \ 

\    \ 

A-^ 

\      ■ 

— ^ 

C28    (871)    50M 

\-*^\ 


t-l 


COLUMBIA  UNIVERSITY  LIBRARIES  (hsi.stx) 

Rd  61  C865  C.1 

Expnrimnntnl  rrr.nn'f,''  ■■•'0  '^'" '''"'"''/ '^ 


2002120917 


.  \y  \-^'a.=^  O  v-  Mj        Ov  r 


AkY  ISA^/f/^ 


47V 


